http://www.telegraph.co.uk/news/ukn...r-threat-to-London-stations-and-airports.html 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 â€œimminentâ€ threat and the overall threat level had not changed but there was activity from one of a â€œhandfulâ€ of extremist cells that cause concern at any time, leading to an adjustment in policing levels. It is understood that â€œintelligence chatterâ€ 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."