This case remains a puzzle, but maybe coming to an end:
A Vietnamese man pleaded guilty Friday in New York to supporting Al-Qaeda in Yemen, where he learned to build a bomb earmarked to blow up London's Heathrow airport.
Link:http://www.telegraph.co.uk/news/ukne...aeda-link.html

It appears that Pham was extradited to the USA in March 2015, after a protracted legal case over his UK citizenship being revoked by the Home Secretary
...after being charged with travelling to Yemen to receive training at an Al-Qaeda camp.
Link:https://www.thebureauinvestigates.co...s-in-new-york/

Why he was not charged here eludes me as evidence was found upon his arrival @ London Heathrow in July 2011:
A search of his belongings discovered electronic files setting out his links to AQAP as well as a live round of armor-piercing ammunition capable of being used in a Kalashnikov assault rifle.
Link:http://www.telegraph.co.uk/news/ukne...r-charges.html