The Mail on Sunday report said suspected suicide pilots had been detained in the kingdom in recent weeks and had been planning to fly light aircraft packed with explosives into British aircraft. The report quoted UK shadow deputy minister for homeland security, Patrick Mercer, who said: 'My understanding is that they were found on the flight line and that the plan was to fly them into a passenger jet, either about to land or take off.'

The UK Foreign and Commonwealth Office (FCO) confirmed that there was a threat in the kingdom, but did not specify the nature of the threat. 'The threat includes, but is not limited to, residential compounds,' said an FCO statement. 'We are not able to comment on the nature of this information.'

A British Airways spokesman said that the airline had no knowledge of the alleged incident. 'We are in regular contact with the Saudi authorities and the British government and we would not fly unless it was completely safe to do so,' the spokesman said. 'We have not changed our flights to or from Saudi Arabia.'