Four men jailed for a failed London bomb plot have launched a legal bid to overturn their convictions.
Lawyers representing the men convicted of the attempted attacks on 21 July 2005 claim fresh evidence from Sean Doyle, a former scientist at the Forensic Explosives Laboratory (FEL), casts doubt as to whether the bombs were viable.
Muktar Ibrahim, Yassin Omar and Ramzi Mohammed were jailed for life for taking rucksacks packed with explosives on to Tube trains and a bus a fortnight after 7/7.
Manfo Asiedu was jailed for 33 years after he removed the battery from his bomb before throwing it in a bin in a west London park.
During their 2007 trial the men claimed they wanted to carry out a high-profile hoax to protest against the invasion of Iraq.
Papers now lodged with the Criminal Cases Review Commission and Court of Appeal by their lawyers say Mr Doyle said a number of FEL scientists "openly expressed concerns" relating to the work of the prosecution's expert witness, Dr Stuart Black. The lawyers say these doubts were not passed on to the defence at the trial.