Metropolitan Police Commissioner Sir Paul Stephenson, speaking in a national radio interview, described the London Games as "the first Olympics to take place against such a significant terrorist threat".

London’s joy at winning the right to host the 2012 Games was cut short in 2005, when on the day after the International Olympic Committee (IOC) awarded the Olympics to the British capital, Islamic suicide bombers attacked the Tube and bus network in the city, killing 56 and injuring more than 700.

Last month, the Government’s terror alert rating in the UK was raised to "severe".

Asked how he regarded the prospect of ensuring that the London Games are free from terror attacks, Sir Paul said, "I am excited and concerned, in equal measure.

"It is fair to say this will be the first Olympics to take place against such a significant terrorist threat.

"That’s a real concern to me, and I have particular responsibility for ensuring we deliver a safe and secure Olympics."

Terrorists have targeted sporting events ever since the Black September attack on the Israeli team at the 1972 Olympics in Munich, when 11 athletes were killed. At the 1996 Atlanta Olympics, two people died and 111 people were injured as the result of a bombing of Centennial Olympic Park.

Sir Paul, 57, has been in charge of the Metropolitan police since 2008, appointed in controversial circumstances following the resignation of Sir Ian Blair.

It was the first time that the Commissioner of the Metropolitan police had been appointed jointly by the Home Secretary and by the Mayor of London.

As Met Commissioner, Sir Paul has wider anti-terrorism responsibilities, beyond London and throughout the UK.

He said: "I continue to be very concerned about the prospects of terrorist attacks and attempts to attack this country.

"It’s a cause of great concern to me."

Of Olympic security, he said: "We have a huge amount of work to do to ensure that people can come here and enjoy a sporting event.

"This is not a security event, it’s a sporting event, and we’re determined to ensure that we do everything possible to make sure people are safe."


Related stories
November 2009: London Olympics is greatest threat to national security since World War Two warns Government Minister
November 2009: Multi-million pound security boost For London 2012 Olympics
September 2009: Do not compromise Londoners safety for the Olympics says Assembly Member
August 2009: Transport police chief to be 2012 security director
July 2009: Cyber crime biggest threat to London 2012 officials fear