US airports and public transport systems are tightening security today following the terrorist incidents in Britain.

Prime Minister Gordon Brown today warned that the terrorist threat to Britain was “long-term and sustained” and said that security services and the public will have to remain “constantly vigilant”.

London is expected to return to normal today after the disruption caused by the two failed car bombs, but police will be out in greater numbers than usual.

Two fully intact car bombs found in central London hold hundreds of clues about the people behind a suspected terrorist plot that could have killed hundreds.

US authorities are in “close contact” with their UK counterparts over the car bombs discovered in London, the US Department of Homeland Security said today.

A second London car bomb is being inspected by officers, police sources said tonight.

Hundreds of late-night revellers are feared to have been the target of a massive terrorist car bomb left outside a landmark London nightclub.

Part of Park Lane in central London was closed to traffic this afternoon after reports of a suspicious vehicle.

A massive terrorist strike which could have killed hundreds of nightclub revellers in London was foiled by chance today.

Experts said the car bomb found today in a car in London's Haymarket would have created a devastating explosion on the scale of those seen in Baghdad and Israel.

A car bomb defused in central London today was packed with petrol, nails and gas canisters, police have revealed.

Police will be scouring CCTV footage from the scene of today’s discovery but will also be checking images from further afield, experts said today.

Varying reports are emerging of the size of the explosive device found in a car in central London this morning. The device has since been made safe.

Intelligence sources in London said they were keeping an open mind on who was responsible for a car bomb found this morning in London's Haymarket district. The device has since been made safe.

The threat of terror returned to London today after a car bomb was found in the heart of the British capital.

Part of central London was cordoned off today after police discovered an explosive device.