Despite official recommendations, Railtrack has refused to cut the number of contractors it uses for maintenance.

Nearly 1,500 firms now have safety permits allowing them access to tracks with more than 200 involved directly in repairing rails, points and signals.

One of the survivors of the Potters Bar rail crash, novelist Nina Bawden, has called for a public inquiry, while the company responsible for maintenance on that line, Jarvis, yesterday recorded record profits.