Image copyright Department of Justice Handout Image caption Minh Quang Pham was arrested at Heathrow in July 2011

A British citizen who US prosecutors said plotted to carry out a suicide bomb attack at Heathrow Airport has been jailed for 40 years in the US.

Minh Quang Pham, 33, was sentenced in New York for supporting the terror group al-Qaeda in the Arabian Peninsula (AQAP) in 2011.

In January, Pham admitted three counts of terrorist-related activity based on his support for the group.

He denied he intended to carry out his plot and no attack ever occurred.

Pham, a former Vietnamese national who had lived in London, was first arrested in the UK in June 2012 and was extradited to the US in February 2015.

Scotland Yard said its counter-terrorism command provided key evidence that helped shape the case against Pham, also known as Amin, which led to his prosecution.

He pleaded guilty to one count of providing material support to AQAP, one count of conspiring to receive military training from AQAP and one count of possessing and using a machine gun in furtherance of crimes of violence.

'Exceptionally severe sentence'

Prosecutors said Pham was directed by al-Qaeda leader Anwar Al-Awlaki to detonate explosives in Heathrow's arrivals area after spending several months in Yemen being trained by him.

District Judge Alison Nathan said Pham deserved an "exceptionally severe sentence" after he became a trusted asset for the terror group.

Pham had worked as a graphic artist on the group's magazine, Inspire, that was said to be used by the Boston marathon bombers to learn how to make bombs.

During the hearing Pham said he had made a "terrible mistake" that he regretted and sent a letter to the judge to say he renounced all acts of terrorism and extremist ideology.