The UK's security agencies did not have advance warning of an alleged al Qaeda plot to bomb a US-bound plane, according to the UK Government.
Home secretary Alan Johnson said Britain had shared details of the Nigerian suspect, Umar Farouk Abdulmutallab, with the US Government.
Questions have been raised about whether US officials failed to act on that information and US President Barack Obama has faced criticism over lapses in security.
UK intelligence was reportedly aware of Abdulmutallab, whose name was added to a watch list compiled by immigration officials in April 2009.
The suspect studied engineering in London between 2005 and 2008.
Full body scanners will be set up at Heathrow Airport in the UK within three weeks in an effort to tighten security measures.
The scanners will have a 50%-60% chance of detecting explosives such as those prosecutors say were used in the Detroit plot.