Four Muslims serving at least 40 years behind bars for planning unsuccessfully the July 21 London suicide bombings failed in a Court of Appeal to overturn the convictions on Wednesday.
Three judges in London's Woolwich Crown Court dismissed applications brought by Muktar Said Ibrahim, Yassin Omar, Ramzi Mohammed and Hussain osman for leave to appeal.
They were jailed for life last July after being convicted for conspiracy to murder.
Today's ruling was delivered by Sir Igor Judge, Justice Forbes and Justice Mackay, who heard argument in the case last month.
On July 21, 2005, the men had tried to detonate rucksacks laden with explosives on three Underground trains at Shepherd's Bush station, Oval station and Warren Street station, together with a bus in Hackney Road, killing themselves and passengers but the bombs failed to go off.
The attempted attacks came two weeks after four suicide bombers struck in central London, killing 52 people and injuring more than 770.
The Judge also dismissed applications brought by Mohammed and osman against sentence.
Sir Igor said: "These were merciless and extreme crimes. As they were rightly meant to be, the sentences were severe and extreme. Beyond doubt, however, they were utterly justified."
At their trial the four had maintained that the events of July 21 were an elaborate hoax designed to protest against and draw attention to Britain's role in the attack upon and occupation of Iraq.