Plans to fight terror at Heathrow left on roadside

An inquiry has been launched into how a secret police dossier reportedly containing counter-terror plans for Heathrow airport, went missing, Scotland Yard said last night.

The confidential papers, found by a motorist close to terminal 4, reportedly showed 62 sites at the airport where al-Qa'ida was most likely to launch anti-aircraft missile strikes.

Compiled by Scotland Yard's SO18 anti-terrorist Aviation Security team based at Heathrow Police station and dated 26 June 2004, the file allegedly includes patrol times, deployment of rooftop snipers and use of dog units. They also included key facts about escape routes, evacuation plans and road closures.

A Metropolitan Police spokeswoman said that any breach of security was treated "extremely seriously". She said: "We have launched an internal inquiry."

The plans, which have since been returned to the Met, were found by a businessman beside the Southern Perimeter Road at midnight.