Four would-be bombers, who launched a failed plot to terrorise London days after the 7/7 attacks, are to launch a legal bid to overturn their convictions.
The lawyers for the men, who took rucksacks packed with explosives onto tube trains and a bus on July 21st 2005, say a senior scientist has raised concerns about whether the bombs would ever have been able to detonate, but those doubts were not shared with the men's defence.
Papers have been lodged with the Criminal Cases Review Commission and Court of Appeal.
Muktar Ibrahim, Yassin Omar and Ramzi Mohammed were all jailed for life in 2007. The fourth member of the team, Manfo Asiedu, back tracked at the last minute and removed the battery from his bomb, chucking it into a park bin. He was jailed for 33 years.
Scientists originally said the bombs did not explode because the bombers had got the chemical recipe wrong, but the bombers argued that they had deliberately constructed their devices so that they would not explode and that the plot had been a hoax.
But now Sean Doyle, former principal scientist at the Forensic Explosives Laboratory, said a number of scientists "openly expressed concerns" about the work of the original prosecution's expert witness, Dr Stuart Black.
Dr Black argued that the bombs would have detonated. They were convicted along with another defendant, Hussein Osman, who is not part of this attempted appeal.
Before the trial, Doyle told the police he believed the "methodology employed by Dr Black and the interpretation of the results may not be reliable.
"In my opinion, the scientific evidence presented by Dr Black was not treated with the caution required of a novel forensic technique."
But lawyers for the four men said Doyle's doubts were not disclosed to the defence.
Ibrahim, Omar and Mohammed have already had one appeal rejected and must petition the Criminal Cases Review Commission to examine whether there was a miscarriage of justice.
Manfo Asiedu was not part of that challenge so he can directly petition the Court of Appeal.