Commentary: Work with us to defeat the terrorists

The atrocities in Madrid last week have inevitably had an impact on Londoners and how safe we feel in our city. In the past I've made no secret of the threat we face from terrorism. I am not going to pretend otherwise now. The threat is real, and no one can guarantee that London will always be safe from any terrorist attack.

But we have scored real successes against the terrorists, and with a degree of concern and heightened awareness we can further strengthen our defences.

That does not mean I am asking people to worry about the threat in every waking moment or to change their behaviour. To do so would give victory to the terrorists who want to disrupt our democratic and peaceful way of life.

After attacks across the world since 11 September, the effect on police and security services across the globe has been remarkable. We have never before had the sort of cross-border and intercontinental cooperation that now exists between countries which are determined to combat and defeat terrorism. This is also reflected here in the UK. Police and the security services are working more closely than ever to co-ordinate intelligence and plan operational activity.

Since 11 September we have increased the strength of our specialist branches and arrested more than 500 suspects in antiterrorist operations across the country.

About half of these have been charged with terrorism or other offences and a large number are going through the courts.

I have no doubt that our activity and disruption tactics have prevented attacks that could have killed or maimed many people. But we must not forget another reality: that terrorist attacks are usually the result of careful planning. They need people, accommodation, vehicles and finance. To achieve their perverted ends they have to operate and interact with other people, and this is their vulnerability.

Sadly, London has a long history of dealing and coping with terrorism. But the city and those who live and work here have always emerged stronger and more determined. We have learned the lesson that only with the involvement of the public can the police defeat terrorism.

The extra vigilance engendered by the horrific loss of life in Spain must work for us, not against us. Yesterday the Met and our colleagues in the City of London Police joined forces with British Transport Police and Transport for London to launch a new awareness campaign aimed at Underground and train passengers. The campaign was organised before the Madrid bombings, but it could not have been more timely. The London Underground is a public space but a controlled one, with hundreds of staff at stations, extensive CCTV coverage and its own dedicated police resources. The vigilance of three million passengers who use the system every day must not be underestimated.

Of course there can be no room for complacency. But the travelling public provides literally millions of extra eyes and ears to complement staff and the overt and covert police patrols being deployed across the network.

So my message to Londoners and the people who visit our magnificent city is a clear one: Don't let the terrorists win. Go about your everyday business with vigilance and if you spot something suspicious alert police straight away. If we work together in this way we can prevent the horror of Madrid last week coming to London.