24 February 2015
Last updated at 16:56
An MI5 agent (left) sketched without facial details testifies in court
MI5 agents are appearing in a US court for the first time to give evidence in the trial of Abid Naseer, wearing wigs and makeup to hide their identities.
A judge ruled court sketches of the spies must be made with “blank faces” and “generic hair”.
Mr Naseer, who was extradited from the UK in 2013, is accused of plotting bomb attacks in Manchester and New York as part of an al Qaeda conspiracy.
He has pleaded not guilty and denied he was involved in any violent extremism.
Mr Naseer faces life in prison if convicted of the charges against him – providing and conspiring to provide material support to al Qaeda and conspiring to use a destructive device.
Prosecutors have called the testimony of the MI5 agents essential, saying they tracked Mr Naseer in 2009 and were the only witnesses to his alleged preparation to attack a Manchester shopping centre.
Inside the courtroom – Nick Bryant, BBC News
In a courthouse in Brooklyn, we saw the sort of make-up and hair ordinarily associated with Broadway. So determined were MI5 to protect the anonymity of their undercover agents that they wore disguises to conceal their identities.
The first MI5 agent called, who was described in court as Officer 1661, wore glasses, a jet-black wig and also a beard – though it was hard to tell whether his facial hair was real or artificial. He had worked for eight years as a surveillance officer, and described how he had conducted surveillance on the defendant Abid Naseer, who had been given the code name Small Panel.
In court, a balance has had to be struck between security and transparency. Rather than appearing behind screens, then, they wore disguises so that jury members could see their facial expressions and body language, and thus assess their credibility.
Reporters were allowed in the federal courtroom, where cameras are already prohibited, but court artists were told they could only sketch blank faces and “generic hair” rather than producing accurate depictions.
Sketch artists will not be able to give as much detail to the MI5 officers as others in the courtroom
Judge Raymond Dearie had previous approved the wigs and “light” make-up to protect the identifies of the officers.
He ordered courtroom sketch artists to further generalise their appearance over media organisation’s objections.
Evidence from one of the MI5 spies was recorded last month and played in court in Brooklyn last week.
The officer said he followed Abid Naseer onto a coach and observed him watching a video of the 9/11 attacks on his mobile phone.
Mr Naseer (seen here in 2010) was previously arrested in the UK over a bomb plot in Manchester
Mr Naseer was one Abid Naseer was one of a dozen men arrested in Britain in 2009 on suspicion of plotting an attack on shopping centres in Manchester.
No explosives were found but the men were ordered to leave the country. Mr Naseer avoided deportation.
UK officials arrested him again in 2010 at the request of US prosecutors. He was eventually deported after losing an appeal at the European Court of Human Rights.
US prosecutors have argued Mr Naseer was the leader of an al-Qaeda cell in Manchester, who was part of a larger conspiracy planning bomb attacks in multiple countries.
Mr Naseer is representing himself and has said he went online and used email to find a wife, not contact an al-Qaeda handler, as prosecutors have alleged.