By Hannah Thomas-Peter, New York Correspondent
A man who was plotting to blow up the Arndale shopping centre in Manchester has been found guilty of terrorism offences in New York.
The jury convicted Abid Naseer, 28, of providing material support to al Qaeda, conspiracy to provide material support to the terror group and conspiracy to use a destructive device.
The verdict was reached at a federal court in Brooklyn. No date has yet been set for Naseer's sentencing.
During the trial prosecutors argued that Naseer played a major part in a global al Qaeda plot to launch coordinated attacks in Manchester, Copenhagen and New York City.
The attacks were designed to "replicate the devastation" of the attacks on 11 September, 2001.
Greater Manchester Police's chief investigating officer in the case, Detective Superintendent Mark Smith, told Sky News it was "as big a plot as we've seen in the UK, quite seriously".
He said: "The scale of the intended attack, the number of casualties that I think we would have seen in Manchester, would have been comparable to the 7/7 attack."
The court saw photographs of alleged co-conspirator Tariq Ur-Rehman, who was never charged, posing as a tourist at the Arndale centre and other locations.
The prosecution said the images were actually reconnaissance, and that the terror cell had concentrated on locations with glass-fronted shops to maximise casualties.
To assist with the US government's case, serving undercover MI5 agents gave evidence in full public view, disguised with wigs and makeup.
They described how they followed Naseer in March and April 2009, and the jury saw surveillance notes describing him watching a video of the 9/11 attacks on his mobile phone.
Det Supt Smith told Sky News that his operation had learned that Naseer had sent emails to a suspected al Qaeda handler speaking in coded language about an impending "wedding", meaning an attack.
He said: "Those emails indicated that he was ready to attack, and that attack was more than likely going to take place over the following weekend, which would have been the Easter bank holiday weekend."
But Manchester police were rushed into making arrests ahead of schedule when Britain's most senior counter-terrorism officer, Bob Quick, accidentally allowed details of the operation to be photographed as he walked into Downing Street.
Naseer and 11 others were taken into custody, but little evidence was found and all were released without charge.
In 2013 he was extradited to America.
Det Supt Smith said: "It's always disappointing not to be able to prosecute a case in the UK, but having said that, I just wanted to see Abid Naseer brought to justice."
One of the New York plotters who had planned to target the subway system, and who is already in prison, described receiving bomb-making training in Pakistan and Afghanistan.
He told the court how he had been taught to use ball bearings to injure and kill as many commuters as possible.
The prosecution said Naseer had received the same training, and was communicating using the same coded language with the same senior al Qaeda handlers.
Before they rested their case lawyers produced their final piece of evidence - never before seen documents recovered from the raid on Osama bin Laden's compound in Pakistan.
In a court building with a direct view of the 9/11 attack site, they said letters from senior terror chiefs to bin Laden made direct reference to the Manchester plot, and revealed the group's determination to attack America and its allies at home.
Naseer argued that he had come to the UK from Pakistan on a student visa to study and to find a wife.
He told the court that all the evidence against him was circumstantial, but it wasn't enough to convince the Brooklyn jury in federal court room 10A.
Naseer is facing life in prison.
