SECRET plans for the mass evacuation of London after a terror strike have been found on a CD left in a supermarket carrier bag on a train seat heading for Gravesend.

The Government data reveals exactly how police would evacuate millions of panicking people after a terrorist attack. A warehouse worker discovered the bag on a train between London and Gravesend on September 3.

The 68-page dossier headed ‘Operation Sassoon - Metropolitan Police Traffic Plan for the Mass Evacuation of London’ was dated June 3, 2004.

It has been drawn up by senior Metropolitan police officers and members of Deputy Prime Minister John Prescott’s London Resilience Team.

According to the Sun newspaper, who the report was given to, it says: “The type of scenario this plan is designed to address is one that is beyond that of a major incident. It may involve chemical, biological, radiological or nuclear contamination on such a large scale that significant areas of the capital need to be evacuated.

“Mass evacuations will result in casualties and probably loss of life. There is a possibility that the road network will become unusable due to gridlock.”

The report also gives detailed maps of the route to be used in the event of a disaster.

Five Kent towns - Tonbridge, Maidstone, Ashford, Bexley and Orpington - have been earmarked to provide refugee rescue centres providing "covered accommodation with all-weather protection, allowing assembly and processing of evacuees."

Local authorities would also have to lay on short-term accommodation, providing snacks and drinks for the first 24 hours, and then buildings with more substantial meals and sleeping arrangements for 48 hours.

Up to 100,000 people would be transported on 87 trains per hour during such a rescue mission.

Scotland Yard has launched an inquiry into how the dossier went missing.