Police in Britain confirmed on Friday evening that one more massive car bomb set to explode in central London near the first car bomb was defused early Friday morning.

The car was illegally parked near Haymarket and towed to a car pound before staff there alerted police when "it smelled of gas," Sky news reported.

Like the first car bomb found in Haymarket in a metallic green Mercedes, the second one was also packed with petrol, gas cannisters and nails, the second one was also defused and taken away for examination.

Peter Clarke, Deputy Assistant Commissioner of the anti-terrorism branch at the Metropolitan Police, said at a news conference that the second car was a blue Mercedes and was parked a few hundred yards from the first one between Haymarket and Trafalgar Square.

"The vehicle was found to contain very similar materials to the first vehicle in Haymarket," said Clarke, adding "the vehicles are clearly linked."

According to Clarke, "the discovery of a second bomb is obviously troubling and reinforces the need for the public to remain vigilant."

He urged anyone with information about the blue Mercedes to come forward.

Home Secretary Jacqui Smith said on Friday afternoon that Britain is "currently facing the most serious and sustained threat" and authorities are doing everything they can to protect the public.

Following the incident, more police are patrolling London streets and security measures have been boosted at both houses of the Parliament.

Sky news quoted government sources as saying the security services are looking at possible international links which include similar car bombs used by insurgents in Iraq.

The bomb scares remind London residents of the terrorist attacks in the city's public transport in 2005, when 52 innocent people were killed and more than 700 injured.