The police said they believed the attack was linked to the 2007 London car bombs 36 hours before . The vehicle was reported to have contained 60 litres of petrol , gas cylinders , and nails . Scotland Yard reported that while the gas contained in the canisters and the quantity of the canisters remains unknown , further details would be given after they were analysed by forensic experts . The head of Scotland Yard 's counter-terrorism command said , " It is obvious that if the device had detonated there could have been serious injury or loss of life . " The device could not have detonated , because it lacked an oxidiser , according to a columnist for The Register ( UK ) . This information may have originated from an interview of former CIA counter-terrorism officer Larry Johnson , conducted by Keith Olbermann of MSNBC on 29 June . According to '' Sky News '' , the gas cylinders contained propane , used for patio heaters . A second bomb was later found in a blue Mercedes-Benz 280E believed to have been left in the same area at around the same time . The illegally parked car received a parking ticket in Cockspur Street at 02:30 . At about 03:30 the car was transported to the Park Lane car pound . Staff left the car in a public area after smelling petrol fumes and alerted police on hearing about the first bomb
2007 London car bombs
2007 London car bombs
2007 Glasgow Airport attack