Train stations across London have been put on high alert amid fears of a terrorist attack on transport hubs.

British Transport Police cancelled leave and called in extra officers after intelligence was received that terrorists could be planning attacks.

A security source said there was no “imminent” threat and the overall threat level had not changed but there was activity from one of a “handful” of extremist cells that cause concern at any time, leading to an adjustment in policing levels.

It is understood that “intelligence chatter” suggested that transport hubs in London could be a target.

It was unclear last night whether the terrorists were discussing suicide bomb attacks, or Mumbai-style shootings, or a combination of methods.

A Whitehall source said: “The assessment of the threat to transport hubs has been revised. The view is that there is a greater risk than before, so steps are being taken as a precaution.”

There have been two serious terrorist plots in the last few weeks that have been linked to Britain.

On December 11 a suicide bomber blew himself up in Stockholm, Sweden while heading towards the central train station.

In Copenhagen, Denmark, last week, police arrested three men with a submachine gun, silencer and ammunition who were allegedly planning a Mumbai-style shooting spree.

Both plots had links to Britain – the Stockholm bomber, Taimour Abdulwahab al-Abdaly, had been living in Luton, while the alleged Danish terrorist cell had links to a network in Derby, the Daily Telegraph reported on Thursday.

 (Source: Telegraph UK)