London bombers seek fresh appeal
Four men jailed over a failed plot to bomb London in 2005 have launched a legal bid to overturn their convictions.
Lawyers for the men convicted of the 21 July attacks say a senior scientist raised concerns about key evidence.
The men say doubts about whether their bombs were viable were not disclosed to the defence during their 2007 trial.
Papers have been lodged with the Criminal Cases Review Commission and Court of Appeal.
Muktar Ibrahim, Yassin Omar and Ramzi Mohammed took rucksacks packed with explosives onto tube trains and a bus in July 2005, just a fortnight after four earlier bombers had killed 52 commuters. They were all jailed for life.
Manfo Asiedu backed out at the last minute and removed the battery from his bomb before ditching it in a bin in a West London park. He was jailed for 33 years.
The plots involved virtually identical homemade devices - but the trial of the 21 July bombers heard that the second set of bombs failed because the bombers had got the chemical recipe wrong.
During the 2007 trial, the men who boarded trains and a bus argued that they had deliberately constructed their devices so that they would not explode.
They said they had wanted to carry out a high profile hoax to protest against the invasion of Iraq. They were convicted along with another defendant, Hussein Osman, who is not part of this attempted appeal.
Lawyers acting on behalf of the men argue that the convictions were unsafe.
They point to concerns raised by Sean Doyle, former principal scientist at the Forensic Explosives Laboratory, a top security government facility, which carries out extensive tests on all bombs found in the UK. The results of those tests later formed the heart of prosecutions.
In a witness statement, Mr Doyle says a number of FEL scientists "openly expressed concerns" relating to the work of the prosecution's expert witness, Dr Stuart Black.
The bombs used during the two July 2005 attacks were based on a chemical used to bleach hair. They had never been seen before in the form they were used. That prompted government scientists to undertake a research programme to understand how they had been constructed and the dangers they posed.
Dr Black argued that the bombs were viable and would have worked.
But the papers submitted by the lawyers say that Mr Doyle told the Metropolitan Police that 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."
The lawyers for the four men argue that there was a failure to disclose Mr Doyle's doubts to the defence, meaning the convictions are unsafe.
Mr Doyle says in his statement that he left the FEL on good terms and moved to New Zealand for family reasons, where he continues to work as a scientist.
Osman and the three other men who tried to detonate their devices have already had one appeal rejected. They can only try again by asking 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.