Metropolitan Police commissioner, Sir John Stevens, has warned that a terror attack on London is ‘inevitable’.

Speaking at the Mayor of London’s press conference, Sir John said that it is not just the transportation system that could be targeted by terrorists.

He said: “We are not just talking about the tube and the rail system. We are talking about London in general – the nightclubs and pubs.”

“We know, from experience in Bali, that al-Qaeda attacks clubs. There is now a need for everyone to be alert,” he said.

The call comes a week after a set of train bombs killed over 200 people in Madrid.

Colin Dawson, British Association of Leisure Parks, Piers and Attractions (BALPPA) chief executive, said: “A large number of our members can be described as soft when it comes to protection against the level of threat posed by terrorism.

“However, while there is no place for complacency, I do believe that many have identified the threat and have an adequate level of security to ensure visitors’ safety,” he said.

A recent poster campaign on the London tube, aimed at making commuters aware of the danger posed by unattended bags, could be extended to other public places – including leisure facilities.

Peter Clarke, head of the terrorism branch, said: “We will do whatever is necessary to protect the public from harm. Public vigilance is vital at all times, not only when travelling on the tube or rail network.”

The Metropolitan Police also announced that it was stepping up the numbers of patrols on the underground system including – for the first time – plain clothes counter terrorist patrols in key locations. Details: www.met.police.uk