Six suspected IRA terrorists thought to be behind a string of bomb attacks in Britain are facing new police probes after the Government withdraw controversial letters insisting they were no longer wanted . The fugitive paramilitary suspects had all received so-called 'comfort letters ' under a peace deal negotiated by Tony Blair . telling them they could return to the UK without fear of being charged . But the letters only came to light last year after the collapse of the terror trail of IRA suspect John Downey , who was accused of murdering four soldiers in the 1982 Hyde Park bombing in London . Tony Blair negotiated a deal with Sinn Fein in which on-the-run terror suspects not wanted by police received 'comfort letters ' The case against Mr Downey was thrown out after he produced a letter from the Government telling him he was no longer wanted and was free to travel to the UK . In the fall-out from the trail 's collapse , Government ministers launched an inquiry into the letters – and insisted they were not 'get out of jail free cards ' for terrorists . Following the Government 's intervention detectives now believe these 'comfort letters ' do not protect suspects from prosecution , documents leaked to the Telegraph reveal . The Police Service of Northern Ireland wrote to MPs on the Northern Ireland affairs select committee last week , revealing the major new phase in its inquiries into the 'on the run ' cases . In the letter , Will Kerr , the Assistant Chief Constable , said the PSNI did not believe there was any barrier to prosecuting 'on the run ' suspects who had been sent 'comfort letters ' – because Coalition Government ministers have recently said the letters had no legal force . 'Whilst prosecutorial challenges may still lie ahead , the obstacles to investigating , arresting and charging suspects appear to have been removed , ' Mr Kerr said . The PSNI will 'prioritise ' re-examining the cases of 36 'on the runs ' whose status was changed from 'wanted ' to 'not wanted ' during the scheme run by Mr Blair 's government under which Mr Downey was mistakenly given a letter of assurance . It is understood that 'comfort letters ' were given to suspects in the Harrods car bomb in 1983 , which killed six and injured 90 , and the Remembrance Day bombing in Enniskillen in 1987 . Tony Blair said the peace process with Sinn Fein leader Gerry Adams ( right ) and Martin McGuinness would have collapsed without the letters . Other atrocities under investigation could include the Regent 's Park bombing , in which seven military bandsmen were killed , on the same day as the Hyde Park bombing in 1982 , and the 1984 Brighton bomb , which targeted the Grand Hotel where Margaret Thatcher 's Cabinet members were staying , killing five people and injuring 34 . It comes as MPs prepare to publish a year-long inquiry into the 'comfort letters ' scheme . As part of the peace deal bringing an end to the conflict in Northern Ireland , IRA terrorists serving prison terms were let out of prison early . But this left the problem of fugitive terror suspects who had never faced trial . In a controversial agreement was reached between Mr Blair and Sinn Fein , police checks would be carried out and those who were no longer wanted would be sent a letter informing them of that fact . IRA terror suspect John Downey was wrongly sent an immunity letter . Mr Blair has insisted that only those individuals who were genuinely not wanted by police , and were therefore not going to face trial , were supposed to have received OTRs . He also insisted the scheme was 'not secret ' , even though leading Northern Ireland politicians , including Lord Trimble , who was First Minister of Northern Ireland from 1998 to 2002 , and senior police chiefs in the province were unaware of it . For the past 12 months , MPs on the Northern Ireland affairs select committee have been investigating the on the run scheme . In a report to be published on Tuesday , the committee is expected to raise questions over whether the policy of sending 'comfort letters ' to IRA suspects during Mr Blair 's final months in office was lawful . Mr Blair has insisted the Northern Ireland peace process would have collapsed without the controversial scheme giving immunity from prosecution to republican terror suspects – the so-called 'on the runs ' . The scheme , set up by the Labour government in 1999 , assured more than 200 paramilitary fighters that they were no longer being hunted by the police . Some 95 recipients of the so-called 'comfort letters ' were linked to almost 300 murders . Under hostile questioning from the Commons Northern Ireland affairs committee , Mr Blair refused to apologise for setting up a process which victims said effectively handed the recipients 'get out of jail free ' cards . He told MPs : 'If I had been saying we are not dealing with this in any way at all… I think it is likely that the peace process would have collapsed , ' he said . ' I wanted to put the death , destruction , terrorism and misery to an end . I could n't bring back those people who had died during the Troubles but I was trying to make sure there would not be further victims . '
Fugitive paramilitary suspects had received so-called 'comfort letters ' 'On the runs ' not wanted by police were told they could return to the UK . Letters emerged in trial of the 1982 Hyde Park bomb suspect John Downey . But the Government have insisted the letters do not provide immunity . The police have now confirmed they are probing six IRA suspects .