Media playback is unsupported on your device Media caption Witnesses describe how the attack near the Houses of Parliament unfolded 
 
 The Westminster attacker was British-born and known to the police and intelligence services, Prime Minister Theresa May has revealed. 
 
 She told MPs he had been investigated some years ago but was not part of the current intelligence picture. 
 
 The so-called Islamic State group has said it was behind the attack. 
 
 Eight arrests in London and Birmingham followed the attack that has left four dead - PC Keith Palmer, Aysha Frade, Kurt Cochran and the attacker. 
 
 Mrs Frade worked at a London college, while Mr Cochran was from Utah, in the US, and visiting the capital with his wife Melissa, who is in hospital with serious injuries. 
 
 According to a family statement, the couple had been celebrating their 25th wedding anniversary and were due to return to the US on Thursday. 
 
 PC Palmer was a 48-year-old father, who was an unarmed member of the parliamentary and diplomatic protection squad, with 15 years' service. 
 
 A JustGiving page set up to raise money for the family of PC Palmer reached its initial target of £100,000 within 24 hours, but the target has since been doubled. 
 
 In the attack on Wednesday afternoon, a man drove a car along a pavement on Westminster Bridge, knocking down pedestrians, creating panic and leaving dozens injured. 
 
 After crashing his car into railings, the attacker ran towards Parliament where he stabbed PC Palmer. Armed police shot dead the attacker in the grounds. 
 
 Seven of those injured are still in hospital in a critical condition. A further 29 had been treated in hospital, police said. 
 
 Car hire company Enterprise said the vehicle had been rented from its Spring Hill depot in Birmingham. 
 
 Prime Minister Theresa May paid tribute to PC Palmer saying: "He was every inch a hero and his actions will never be forgotten." 
 
 She also said one of three police officers who had been injured as they returned from an event to recognise their bravery was in a stable condition. 
 
 She told MPs, many of whom had been caught up in the commotion on Wednesday: "We will never waver in the face of terrorism." 
 
 Media playback is unsupported on your device Media caption Mr Cleverly fought back tears as he spoke about his friend Keith Palmer 
 
 An emotional James Cleverly MP asked Mrs May to consider recognising posthumously the "gallantry and sacrifice" made by PC Palmer, who he knew from his time in the Army. 
 
 The so-called Islamic State claimed through its news agency that the Westminster attacker had been a "soldier of the Islamic State". 
 
 Image caption (From left) PC Keith Palmer, Kurt Cochran and Aysha Frade all died in the attack 
 
 Mrs Frade worked at a London sixth-form college just a few hundred metres from Westminster Bridge, which has now reopened. 
 
 The principal at DLD College, Rachel Borland, said she was "highly regarded and loved by our students and by her colleagues". 
 
 Mrs May said 12 Britons had been admitted to hospital and other victims included three French children, two Romanians, four South Koreans, one German, one Pole, one Irish, one Chinese, one Italian, one American and two Greeks. 
 
 Thierry Terret, who is in charge of schools in Brittany, said the three injured students were not in a life-threatening condition and were on their way home. 
 
 Analysis: The PM's carefully-chosen words 
 
 Media playback is unsupported on your device Media caption Prime Minister Theresa May said MPs were meeting as normal to show "we are not afraid" 
 
 By Dominic Casciani, home affairs correspondent 
 
 The prime minister's carefully-worded statement that the killer was once investigated raises more questions than it currently answers. 
 
 It appears that the individual was discounted as a "peripheral figure" on the edge of some other operation. She didn't say whether that means he was considered and discounted for good reason by MI5 intelligence officers, investigated for a criminal offence by detectives or even ever arrested. 
 
 However, she also stressed he was not part of the "current intelligence picture" - and that means he wasn't currently on the radar at all. This points to the very difficult dilemma faced by security services combating these kinds of threats. 
 
 Every day they have to prioritise, or triage, who to pursue and who to discount. People who were once a threat change their thinking. They grow up, have kids and settle down. MI5, meanwhile, is tasked with focusing on those they know of with the most advanced plans. 
 
 Some of those they discount, or temporarily turn away from, later turn out to be more dangerous than initially thought. They include the ringleader of the 7/7 bombings and one of the two men who killed Fusilier Lee Rigby. 
 
 Intelligence is never a complete picture - it is not even like a jigsaw with missing pieces. It's a case of trying to interpret fragments of information that rarely amount to a whole. 
 
 Westminster attack 22 March 2017 4 people killed 40 injured 12 Britons in hospital 
 
 3 French children injured 
 
 9 other nationalities affected 
 
 8 arrests made 
 
 Earlier, Acting Deputy Commissioner Mark Rowley said seven arrests had been made during raids in London and Birmingham - an eighth was announced several hours later. 
 
 The BBC understands that searches and arrests have been carried out in Forest Gate, east London, Wales, Surrey and Sussex, as well as in Birmingham. 
 
 "It is still our belief - which continues to be borne out by our investigation - that this attacker acted alone and was inspired by international terrorism," Mr Rowley said. 
 
 "To be explicit, at this stage we have no specific information about further threats to the public." 
 
 In other developments: 
 
 The Queen said her "thoughts, prayers, and deepest sympathy" are with all those who have been affected by the "awful violence" 
 
 Security at Parliament will be reviewed, says Defence Secretary Sir Michael Fallon 
 
 A candlelit vigil will be held in Trafalgar Square in central London on Thursday evening 
 
 MPs held a minute's silence before Parliament continued business as normal 
 
 People worried about family and friends can call the police casualty bureau on: 0800 056 0944 or 0207 158 0010. Anyone with images or footage of the incident can send them to ukpoliceimageappeal.co.uk 
 
 Image copyright Getty Images Image caption A woman lays flowers near the scene of the attack 
 
 Image copyright Getty Images Image caption Forensic officers scour Parliament Square 
 
 Image copyright EPA Image caption A photo of PC Palmer is placed among floral tributes on Whitehall 
 
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 Please include a contact number if you are willing to speak to a BBC journalist. You can also contact us in the following ways: ||||| Here is the full statement on the Westminster terror attack made by Mark Rowley just now: 
 
 "Good morning - I am here to update you on our ongoing counter-terrorism operation following the horrific attack in Westminster. 
 
 "Greater clarity is now developing regarding the casualty figures as we have now collated information from the public and five hospitals - the latest figures I have are that there are currently four dead and 29 people were treated in hospital. 
 
 "We are still collating numbers of walking wounded and of those in hospital sadly seven of them are in a critical condition. 
 
 "Tragically the deaths included Pc Keith Palmer who was protecting Parliament, and two members of the public - a woman aged in her mid 40s and a man aged in his mid 50s. 
 
 "The fourth man of course was the terrorist who was shot dead by armed police at the scene. 
 
 "Hundreds of detectives have been working through the night and during that time I can confirm we have searched six addresses - and made seven arrests. The inquiries in Birmingham, London and other parts of the country continue. 
 
 "It is still our belief - which continues to be born out by our investigation - that this attacker acted alone yesterday and was inspired by international terrorism. 
 
 "To be explicit - at this stage, we have no specific information about further threats to the public. 
 
 "Clearly our investigation is ongoing - developing all the time - and is focused on his motivation, his preparation and associates. 
 
 "I do recognise that the media are making progress in identifying the attacker - I would continue to ask that his name is not published whilst we are at such a sensitive stage in our investigation - and as I state still conducting arrests and searches. 
 
 "The large and complicated crime scene remains in place and our work there continues - I would like to thank everyone for their support and patience as we finish this work. 
 
 "As people are out and about on the streets of the Capital this morning they will see more police officers on duty - armed and unarmed - and a mix of British Transport Police and the City of London. 
 
 "We have cancelled some leave and increased some duty hours and are working to make sure that we can out in force to reassure the public. 
 
 "We must not allow terrorists to create discord, distrust and fear. 
 
 "The police stand with all communities - later today a meeting of faith leaders will be held here at New Scotland Yard. 
 
 "Whilst our work to investigate and understand what happened yesterday continues with vigour - we must also reflect. 
 
 "I want to thank the public for their support and all their good wishes - I know it is appreciated by all those men and women who are out there today protecting us. 
 
 "Finally, I would also like to ask the public for their continued help and continued vigilance and if you see anything that causes you concern or raises your suspicions do not hesitate to call us - 0800 789 321 - or in an emergency 999. Thank you." ||||| Image copyright AP Image caption Khalid Masood was shot at the scene of the Westminster attack 
 
 Police have identified Khalid Masood as the man who carried out the Westminster attack, as the death toll rose to five. 
 
 Masood, 52, was born as Adrian Elms in Kent and was shot dead by police. He had not been the subject of any current police investigations. 
 
 PC Keith Palmer, 48, Aysha Frade and US tourist Kurt Cochran, 54, were killed on Wednesday, while a 75-year-old man died on Thursday evening. 
 
 The so-called Islamic State group has said it was behind the attack. 
 
 Three women and five men were arrested in London and Birmingham on suspicion of preparation of terrorist acts following Wednesday's attack. 
 
 A woman aged 39 was arrested in east London 
 
 A 21-year-old woman and a 23-year-old man were arrested in Birmingham 
 
 A 26-year-old woman and three men aged 28, 27 and 26 were arrested at another address in Birmingham 
 
 A man aged 58 was arrested at an address in Birmingham 
 
 The Met Police says detectives are continuing to search a number of addresses, including one in Carmarthenshire, three in Birmingham and one in east London. Addresses in Brighton and south-east London have also been searched. 
 
 'We will defeat them' 
 
 Home Secretary Amber Rudd told those gathered for a candlelit vigil in London's Trafalgar Square on Thursday evening that terrorists "will not win". 
 
 "We are all connected and today we showed that by coming together, by going to work, by getting about our normal business, because the terrorists will not defeat us. We will defeat them," she said. 
 
 Masood drove into pedestrians on Westminster Bridge before crashing his car into railings and then running into the grounds of Parliament, armed with a knife. 
 
 He stabbed PC Palmer before being shot dead. 
 
 The Metropolitan Police said there had been no prior intelligence about Masood's intention to carry out an attack. 
 
 But he was known to the police and his previous convictions included causing grievous bodily harm, possession of offensive weapons and public order offences. He was believed to have been living in the West Midlands. 
 
 Masood is believed to have lived at various times in Crawley, West Sussex, and Rye and Eastbourne, both in East Sussex. 
 
 He also appears to have been convicted of a knife crime in 2003 in Eastbourne. 
 
 Image caption (From left) PC Keith Palmer, Kurt Cochran and Aysha Frade all died in the attack 
 
 His first conviction was in November 1983 for criminal damage and his last in December 2003 for possession of a knife. 
 
 He had not been convicted of any terrorism offences. 
 
 Car hire company Enterprise said the vehicle used in the attack had been rented from its Spring Hill depot in Birmingham. 
 
 The BBC understands Masood hired the Hyundai SUV in person, giving his profession as a teacher. 
 
 The Department for Education said it had no record of him having worked as a qualified teacher in English state schools. 
 
 It appears that he styled himself as an English tutor at one point. 
 
 At the Trafalgar Square vigil 
 
 Image copyright Reuters 
 
 By Jodie Halford, BBC News 
 
 People gathered in Trafalgar Square stood together quietly, flanked by police officers with the sound of helicopters a constant presence above. 
 
 The people of London and visitors to the city came together to remember the people who lost their lives in Wednesday's attack. The word "solidarity" was heard over and over again. 
 
 Candles were laid on the floor and on the steps leading to the National Gallery, waiting to be lit in memory of those who died. 
 
 As the bells of St Martin's in the Fields chimed, the crowds fell silent and paused to think about Wednesday's events. 
 
 Some filmed the scene on their phones, some cast glances across the crowds, but the focus was on the candles on the steps leading up to the National Gallery, above which MPs, religious figures and others stood in a line to pay their respects. 
 
 'Business as usual' for defiant Londoners 
 
 PC Palmer, who was stabbed in the grounds of Parliament, was a father. 
 
 He was an unarmed member of the parliamentary and diplomatic protection squad, with 15 years' service. 
 
 His family said in a statement that he would be remembered as a "wonderful dad and husband". 
 
 'Brave and courageous' 
 
 They also described him as "a loving son, brother and uncle. A long-time supporter of Charlton FC. Dedicated to his job and proud to be a police officer, brave and courageous. A friend to everyone who knew him. 
 
 "He will be deeply missed. We love him so much. 
 
 "His friends and family are shocked and devastated by his loss and ask that they are left to grieve alone in peace." 
 
 Image copyright Charlton Athletic FC Image caption Charlton Athletic paid tribute to PC Palmer by placing a scarf on the season-ticket holder's seat 
 
 A JustGiving page set up for the family of PC Palmer reached its initial target of £100,000 on Thursday afternoon, less than 24 hours after it had been set up. 
 
 The amount pledged has now passed £320,000, after the target was raised several times. 
 
 The Met said that as a mark of respect, the constable's shoulder number, 4157U, would be retired and not reissued to any other officer. 
 
 Mrs Frade worked at a London college, while Mr Cochran was from Utah, in the US, and had been visiting the capital with his wife Melissa, who is in hospital with serious injuries. 
 
 According to a family statement, the Cochrans had been celebrating their 25th wedding anniversary and were due to return to the US on Thursday. 
 
 Mrs Frade and Mr Cochran were killed on Westminster Bridge. 
 
 Mrs Frade worked at a London sixth-form college, just a few hundred metres from the bridge. 
 
 The principal at DLD College, Rachel Borland, said she was "highly regarded and loved by our students and by her colleagues". 
 
 In other developments: 
 
 The Queen said her "thoughts, prayers, and deepest sympathy" were with those affected by the "awful violence" 
 
 MPs held a minute's silence before Parliament continued business as normal 
 
 Prime Minister Theresa May spent 40 minutes visiting the injured in hospital 
 
 People worried about family and friends can call the police casualty bureau on: 0800 056 0944 or 0207 158 0010. Anyone with images or footage of the incident can send them to ukpoliceimageappeal.co.uk 
 
 Police have said five people remain in a critical condition in hospital and two have life-threatening injuries. 
 
 A total of about 40 people had been treated in hospital, police said. 
 
 A Romanian couple injured in the attack have been identified as Andrei Burnaz and Andreea Cristea. The Romanian embassy in London has confirmed that Ms Cristea is the person who fell from Westminster Bridge during the attack. 
 
 The casualties also included 12 Britons, three French children -who have since returned home -, four South Koreans, one German, one Pole, one Irish, one Chinese, one Italian, one American and two Greeks. 
 
 Get news from the BBC in your inbox, each weekday morning 
 
 Have you been affected by recent events? If you are willing to do so, share with us by emailing haveyoursay@bbc.co.uk. 
 
 Please include a contact number if you are willing to speak to a BBC journalist. You can also contact us in the following ways: ||||| An attacker who ran over several pedestrians on London’s Westminster Bridge before stabbing a police officer in the Houses of Parliament, killing three people and leaving 29 more injured in hospital before being killed by police, has been named by police as 52-year-old British-born Khalid Masood. 
 
 "Masood, aged 52 (25.12.1964), was born in Kent and detectives believe he was most recently living in the West Midlands. Masood was also known by a number of aliases," read a statement from London Metropolitan Police. 
 
 "Masood was not the subject of any current investigations and there was no prior intelligence about his intent to mount a terrorist attack. However, he was known to police and has a range of previous convictions for assaults, including GBH, possession of offensive weapons and public order offences. 
 
 Keep up with this story and more by subscribing now 
 
 "His first conviction was in November 1983 for criminal damage and his last conviction was in December 2003 for possession of a knife. He has not been convicted for any terrorism offences." 
 
 The naming of the attacker followed the arrest of eight people in connection with the incident after police raided six addresses. 
 
 Earlier in the day, the Amaq News agency, which is often used by the Islamic State group to broadcast propaganda, said ISIS had claimed responsibility for the attack: "A soldier for the Islamic State carried out the operation in answer to calls to target the people of coalition states." 
 
 There was no confirmation that ISIS had directed the attack and British authorities didn't note any connection between Masood and the jihadist group. However, the incident was similar in nature to a series of attacks conducted in Europe using vehicles in recent months, notably in Nice and Berlin. 
 
 The attacker drove a car through pedestrians on Westminster Bridge, killing two people, before crashing into the railings outside the Houses of Parliament. He emerged from the vehicle and attempted to make his way into Parliament. Armed with a knife, he stabbed and killed unarmed police officer Keith Palmer before he was shot by armed police. 
 
 The attacker later died from his injuries. The two victims in addition to the police officer were named as London teacher Aysha Frade and American tourist Kurt Cochran. 
 
 Speaking Thursday morning, British Prime Minister Theresa May did not name the attacker but said that he was known to authorities. 
 
 “The man was British-born and some years ago was once investigated by MI5 in relation to concerns of violent extremism," she said in Parliament. "He was a peripheral figure. His case was historic. He was not part of the current intelligence picture.” 
 
 May called the attack "an act of terrorism aimed at trying "to silence our democracy." ||||| But the complex is by a busy street, and some lawmakers still wonder whether some of the security was designed with the idea of fending off the type of attacks once mounted by the Irish Republican Army, which in 1979 assassinated a Conservative lawmaker, Airey Neave, using a car bomb in Parliament. 
 
 “I am shocked, but I am not surprised,” Chris Bryant, a Labour lawmaker, said of the latest attack. “We have always known that a marauding attack by an individual would be the most difficult to prevent.” 
 
 On Thursday, with tightened security, lawmakers crowded into the parliamentary chamber determined to show that they would not be deterred. Ed Miliband, a former leader of the opposition Labour Party, said the mood had been one of “shock and determination and also admiration for the job that the security people are doing.” 
 
 “I think we are seeing people’s increased determination to carry on with their normal business,” he said. ||||| These crawls are part of an effort to archive pages as they are created and archive the pages that they refer to. That way, as the pages that are referenced are changed or taken from the web, a link to the version that was live when the page was written will be preserved.Then the Internet Archive hopes that references to these archived pages will be put in place of a link that would be otherwise be broken, or a companion link to allow people to see what was originally intended by a page's authors.The goal is to fix all broken links on the web . Crawls of supported "No More 404" sites.
– Details are still trickling out about Wednesday's terror attack in London, and the BBC and the New York Times report that the attacker was identified Thursday by Metropolitan Police as 52-year Khalid Masood, who had been convicted for a series of non-terrorism-related crimes over a span of at least 20 years. A police statement says Masood also had a "number of aliases," per Newsweek. In a speech earlier Thursday before Parliament, Prime Minister Theresa May said the attacker was born in Britain (the BBC notes Masood was born in Kent) and had been on the radar of law enforcement and intelligence agencies some time ago during a probe into violent extremism, the BBC reports. "Our working assumption is that the attacker was inspired by Islamist ideology," she said, per the New York Times. However, May added that Masood (whom she didn't identify by name), who was shot dead by cops in the attack that killed three others, was a "peripheral figure" on the Islamist extremist scene and hadn't recently been under the microscope. ISIS has claimed responsibility for the attack, per the AP and the Telegraph, with a statement by the group's propaganda outlet stating that the attacker was a "soldier" of the Islamic State. Meanwhile, London Mayor Sadiq Khan posted a video statement of his own in which he noted, "Londoners will never be cowed by terrorism," per the Guardian. Khan also said, per journalist Christiane Amanpour's Twitter feed, he won't be commenting on the diss against him by Donald Trump Jr., noting, "I've been doing far more important things over the last 24 hours."