Pubs and buses are targets

London's terror alert was dramatically widened today to include buses, nightclubs, pubs and the road system.

In a grim warning Metropolitan Police Commissioner Sir John Stevens said there was an "inevitability" about a terror attack on the capital. He made clear that after the devastation of rush-hour trains in Madrid last week, Londoners must be vigilant about strikes against so-called soft targets.

"We are not just talking about the Tube and the rail system," he said. "We are talking about London in general. We are talking about buses, nightclubs, pubs and roads. We know from experience in Bali that al Qaeda attack clubs. There is a need for everyone to be alert."

Baggage checks may also be introduced at mainline rail stations with other tough new security measures.

Sir John's warning came as senior police sources confirmed that anti-terrorist branch detectives are investigating strong links between the Madrid bombings and London. A team of officers, including a senior anti-terrorist branch officer, a forensic science expert and an interpreter began work in Madrid today liaising with the Spanish authorities.

The Commissioner said the police and security services were working flat out to counter terrorist attacks on London.

He refused to comment on the possible links between the Madrid attack and al Qaeda members in London but would not rule out interviewing suspects being held under the Anti-Terrorism Act or travelling across the world to help find vital clues about possible terror strikes.

Sir John said: "We will go where the evidence takes us. If that takes us to Belmarsh (prison), that is where we will go." Sources confirmed Sir John was referring to jailed Islamic cleric Abu Qatada, who is thought to be Osama bin Laden's " ambassador in Europe".

The fundamentalist preacher is detained indefinitely without charge at Belmarsh after being classified as a suspected international terrorist by Home Secretary David Blunkett.

A Home Office spokesman said: "If there is an allegation or information which police wish to explore, they can interview any person detained under the Anti Terrorism Crime and Security Act, as indeed they can interview any prisoner.

"It is a matter for Scotland Yard who they wish to talk to and we would not comment on that."

At a joint press conference with Mayor Ken Livingstone this morning, Sir John told how the Met is recruiting an extra 100 officers to the anti-terrorist branch to add to the additional 680 brought in since the September 11 attacks.

Police and MI5 officers were now working in joint teams to counter terrorism.

Sir John said: "We can defeat terrorism. Communities can defeat terrorism. But we need the public to support us, to report suspect packages or people acting suspiciously."

He added police had foiled a number of attacks on the capital since September 11. The Met and security services had arrested 520 people of which 90 were facing trial this year for terrorist offences. Mr Livingstone emphasised London remained

the safest city in the world. The majority of the Tube and rail network was covered by CCTV which would make it difficult for bombers to escape unidentified.

However, he admitted: "It would be miraculous if, with all the terrorist resources arranged against us, if terrorists did not get through, and given that some are prepared to give their own lives, it would be inconceivable that someone does not get through to London. We have known all along there are people trying to come here and take lives.

"There are people out their who will take life in the hundreds and thousands." Meanwhile, police say they are considering tough new security measures for railway passengers. Undercover officers have already been deployed on the Underground.

One of the key measures is more training for staff to spot potential terror suspects. But security officials are resisting plans to introduce airline style baggage checks with metal detectors or X-ray scanners.

Security and transport officials are examining the possibility of introducing similar checks to those used by Eurostar at Waterloo, though these are not considered practical for widespread use.

The moves come as British Transport Police launched a major campaign to enlist the help of London Underground's three million passengers to spot suspicious packages.