Story highlights

Prosecutor: One alleged jihadist described the plan as "another 9/11"

The attack's scale could have been bigger than the 2005 London bombings, he says

The accused men deny the charges

They would face maximum sentences of life in prison if convicted

London CNN  — 

Three men accused of plotting a suicide bombing campaign in Britain went on trial Monday.

If authorities hadn’t foiled the plan, the scale of the terrorist attack might have been bigger than the 2005 London bombings that killed more than 50 people, prosecutor Brian Altman said. One of the alleged jihadists described the plot as “another 9/11,” he said.

Irfan Naseer, Irfan Khalid and Ashik Ali were arrested in September 2011 in what authorities called a major operation.

Read more: Four appear in UK court on terror charges

Altman told jurors that the men planned to use up to eight bombs inside rucksacks in suicide attacks aimed at causing mass casualties.

In the house where they allegedly researched and experimented with bombs, investigators found an audio recording of slain al Qaeda cleric Anwar al-Awlaki, Altman said.

If they were found guilty of engaging in conduct in preparation of terrorist acts, they would face maximum sentences of life in prison. All three men deny the charges.

Read more: Police: 7 men arrested in UK anti-terror operation

Naseer and Khalid are also accused of traveling to Pakistan for terrorist training, and recording martyrdom videos there.

The men began experiments building homemade bombs in a Birmingham flat shortly after returning to Britain, Altman said.

To raise money for the plan, Altman said, the men posed as workers for a Muslim charity and collected 13,500 pounds.

“They were despicably stealing from their own community,” he alleged.

Surveillance recordings conducted by British intelligence officials indicated the men talked about packing the explosives with nails to maximize damage and said the 2005 attacks had “gone a bit wrong” because bombers hadn’t used nails in their explosives to create shrapnel, Altman said.

For the accused men, prosecutors said, former al Qaeda leader Osama bin Laden was “equally inspirational” as the suicide bombers who attacked three London subway trains and a bus on July 7, 2005.

All of three men are from Birmingham, Britain’s second-largest city, authorities said. They were arrested in September 2011.

CNN Terrorism Analyst Paul Cruickshank contributed to this report.