Four British men fueled by the words of a U.S.-born Muslim cleric pleaded guilty on Wednesday to involvement in an al-Qaida inspired plot to spread terror and cause economic damage by bombing the London Stock Exchange at Christmastime.

The men were among nine defendants facing trial in London over an alleged plot to attack the exchange and several other high-profile targets in December 2010. All had initially pleaded not guilty to all the charges against them.

But on Wednesday four of the defendants pleaded guilty at Woolwich Crown Court to involvement in the Stock Exchange plan, and the five other British Muslims to lesser charges.

Mohammed Chowdhury, 21; Shah Rahman, 28; Gurukanth Desai, 30; and Abdul Miah, 25, all admitted preparing for acts of terrorism by planning to plant an improvised explosive device in the toilets of the London Stock Exchange.

Prosecution lawyer Andrew Edis accepted that the men had not planned to kill anyone.

``Their intention was to cause terror and economic harm and disruption,'' he said. ``But their chosen method meant there was a risk people would be maimed or killed.''

Chowdhury, from London, was described by prosecutors as the ``lynchpin'' of the plot. His lawyer, Christopher Blaxland, said Chowdhury admitted planning to plant the bomb, ``with the obvious attendant risk but without any intention to cause death or even injury but with the intention to terrorize, damage property and to cause economic damage.''

The other five defendants admitted attending planning meetings, fundraising for terrorism or possessing copies of the al-Qaida magazine, Inspire.

Prosecutors said they had not made any bombs or set dates for the attacks.

They said the men were not members of al-Qaida but had been inspired by the terror network and the sermons of its Yemen-based American-born cleric Anwar al-Awlaki, who was killed last year in a U.S. drone strike.

Edis said the nine defendants ``were implementing the published strategy of AQAP'' _ al-Qaida in the Arabian Peninsula.

The suspects, then aged between 20 and 30, were arrested in London, Cardiff and Stoke-on-Trent in central England, in what police called the biggest anti-terror raid for two years.
   
Prosecutors said they plotted to send mail bombs to various targets in the run-up to Christmas 2010 and had discussed launching a ``Mumbai-style'' atrocity _ referring to the bomb blasts that killed 166 people in India's financial center in 2008.

The nine defendants were accused of agreeing on targets, discussing materials and methods, and researching files ``containing practical instruction for a terrorist attack.''
   
The men held planning meetings, researched bomb-making and scouted out locations including Parliament, Westminster Abbey and the London Eye Ferris wheel _ not knowing that they were under police surveillance and their homes and cars had been bugged.

A handwritten target list found at one of the defendant's homes listed the names and addresses of London Mayor Boris Johnson, two rabbis, the American Embassy and the Stock Exchange.

The defendants will be sentenced next week, but the judge has already told Chowdhury he will receive 18 1/2 years and Rahman 17 years. They are likely to serve half that time before being eligible for parole.

When police swooped on the suspects in three cities in the early morning of Dec. 20, 2010, they said it was the most significant anti-terror raid for two years.

London has been targeted several times by violent Islamists affiliated with or inspired by al-Qaida.

In July 2005, four suicide bombers killed 52 commuters on three London subway trains and a bus. A year later, U.S. and British intelligence officials thwarted one of the largest plots yet _ a plan to explode bombs on nearly a dozen trans-Atlantic airliners. (AP)