Although British secret service spokesmen have declined to comment on the case, US officials have confirmed that foreign agencies were involved in the operation, which saw a double agent infiltrating Al-Qaeda and stealing an underwear bomb before it was put to use.

The US government claim that there was never any threat to the public during the operation.

Details of the Yemen-based plot to blow up a plane over the States reached the US government in April. The bomb that was built was an upgraded version of the one that failed to detonate on Christmas Day 2009.

The agent was given the bomb and dispatched on a suicide mission, but he instead delivered the device to the CIA.

Both bombs apparently bear the hallmarks of master bomb maker Ibrahim Hassan Tali al-Asiri, who was also heavily involved in a 2010 plot to bomb a Chicago-bound plane with a bomb disguised as a printer cartridge, which also failed to detonate.

In other Yemen news, this week the US also revealed that they had restarted military trailing with the security forces in the country, which had been stopped during political unrest in the country.