PASSENGER trains were urgently diverted this morning when a runaway engineering train started slipping southwards down the Northern Line with no means to stop it and no one at the helm. The train was being towed after breaking down outside Archway statio

PASSENGER trains were urgently diverted this morning when a runaway engineering train started slipping southwards down the Northern Line with no means to stop it and no one at the helm.

The train was being towed after breaking down outside Archway station at 5.25am when it somehow became detached at around 6.44am - slipping back down the line.

Underground staff then rushed to move passenger trains out of the path of the runaway carriage - diverting it to the Charing Cross branch and moving rush hour commuters to the City branch.

An investigation has now been launched into the incident and all similar engineering trains immediately taken out of service.

The train eventually came to a standstill five stops later at Warren Street.

London Underground Director Richard Parry said: "Safety is London Underground's top priority, and we have of course launched an immediate and thorough investigation into this incident to establish the cause. Once that investigation is complete, we will publish the report, making its conclusions and recommendations clear. In the meantime we have prohibited the use of this design of engineering train on the Underground.

"From the start of this incident, an immediate assessment was made and operational decisions taken to minimise the safety risk to our customers and staff.

"Our Engineers are working to restore full services as soon as possible, and we apologise for the inconvenience caused to our customers while we investigate this incident."

The Northern line was suspended between Finchley Central and Archway and Camden Town to Kennington via Charing Cross this morning and remains closed to allow the investigation.