CNN 2010-10-08（在线收听）

The 2008 Mumbai attack caught everyone off guard. No suicide bombing; instead, a high-profile soft target on the waterfront of India's commercial capital. Ten gunmen landed in dinghies, stormed prestigious hotels, shot bystanders in a train station, took over a Jewish community center.

Now, fears that there may be similar conspiracies being hatched against potential targets in Europe, adding to an already-heightened security awareness. The Eiffel Tower was evacuated twice because of terror threats in the last month. Both proved to be hoaxes.

This is Liverpool Street Station and it's right in the heart of London's financial district. And it is exactly the type of soft target that was hit in Mumbai.So just how prepared are London and other European cities for this type of an attack?

Colonel Richard Kemp is a former counter-terror adviser to the British government.

How vulnerable are soft targets like Liverpool Street Station, where we're at?

They're -- they're extremely vulnerable, because it's possible to -- to move into an area like this undetected, cause mayhem and murder, killing people, shooting them, blowing them up with grenades. And it takes, obviously, the police are not going to be -- can't be everywhere ready to handle it immediately.

What the police do is to -- well, obviously, identify the central target areas and make sure they've got plans in place, make sure their tactics are appropriate for dealing as rapidly as they can with it. Otherwise, apart from what the -- the work of the police and the other security agencies, it has to be business as usual in the same way as other terror threats, we can't allow our cities just to grind to a halt. We can't allow ourselves to go into a siege mentality.

Shopping areas like London's Oxford Street are also a concern. There are dozens of CCTV cameras in the area to alert police to suspicious activity. But security experts say the human factor is most important.

Absolutely, first and foremost, is the human factor issues，ensuring that staff are fully trained in every up to date method of detecting, for example, hostile reconnaissance, detecting what's going on during an instant and ensuring that they're able to -- to move the public into a place of safety as quickly as possible.

The key, security experts say, is to stay alert and vigilant, preventing an attack before it happens and that, in turn, demands good intelligence.