The UK Government has now confirmed that security forces were successful in foiling an Al-Qaeda plan which involved hijacking a plane in eastern Europe and flying it into one of the passenger terminal buildings at

London Heathrow Airport.
The government has confirmed that its security agency MI5 received detailed intelligence of the plan in February 2003, which helps to explain the presence of tanks and armoured vehicles at Heathrow at the time.
Reports also suggest that some ministers even considered the possibility of shutting down the airport until the threat was considered to be over. The UK Government says the terror plan was hatched in retaliation for Britain’s decision to send troops in support of America’s invasion of Iraq. It says that the foiled plan also included a mortar bomb attack on a departing passenger plane. Details of the plan were unveiled when the White House recently made public 10 Al-Qaeda plots which it claims have been foiled by the US and its partners, including Britain.