A STEAM train operated by the company behind the 'Harry Potter' locomotive came within seconds of a high-speed collision with a passenger train because the driver was "distracted", an investigation has found.

Investigators said the driver, who had been involved in a previous safety breach a decade before, missed warnings on March 7 2015 because he had "become distracted by activity within the cab and possibly also because he was experiencing a higher workload than normal".

The report by the Rail Accident Investigation Branch (RAIB) also criticised a "weak safety culture" at West Coast Railways (WCR), which also operates the famous 'Hogwart's Express' Jacobite steam train.

The Herald: The Jacobite steam train, operated by WCRThe Jacobite steam train, operated by WCR

The report reveals that the 13-coach Tangmere steam train ran a red light and narrowly missed hitting a passenger service operated by First Great Western when the driver missed a signal warning him to slow down and was subsequently unable to stop before reaching Wootton Bassett Junction in Wiltshire.

The Tangmere shot through the junction and only came to a stop 550 metres (1800ft) later, blocking the path of oncoming trains.

The First Great Western service, en route from Swansea to London Paddington, had passed through the junction only 44 seconds earlier.

No injuries, damage or derailment occurred, but industry watchdog, the Office for Road and Rail (ORR), warned that there could have been a "catastrophic train collision" and stripped WCR of its operating licence for six weeks pending safety improvements.

The ban was eventually lifted just four days before the popular Jacobite steam train was due to launch its summer timetable between Fort William and Mallaig. The ORR later confirmed that it was launching criminal proceedings against the WCR and the driver in connection with the Wootton Bassett safety breach.

The driver, who has 50 years experience in the rail industry, is alleged to have directed a colleague to turn off the Train Protection and Warning System (TPWS) which is designed to apply an emergency brake if the driver makes an error.

The Herald: Crown copyright - RAIBCrown copyright - RAIB

In the RAIB report published today, investigators found that the driver "was unable to reduce the speed of the train by automatically applying the brakes" because the TRWS system had been "rendered ineffective" by the crew.

The report adds: "Isolating AWS in this way was in contravention of the relevant rules but the RAIB has found that it had almost certainly become an accepted practice among some train crews on this locomotive.

"This was probably because warnings from AWS were not always apparent to drivers, who were also anxious to avoid delays resulting from brake demands. Measures intended to prevent the misuse of AWS isolations had either not been adopted by West Coast Railways or had not been effectively implemented."

The Herald: The TangmereThe Tangmere

It emerged in the report that the driver had been involved in one previous SPAD (signal passed at danger) incident in 2005, which also involved him failing to react to a signal at caution.

The cause was said to have been "a loss of concentration as a result of significant difficult events having recently occurred in his personal life", and he was subsequently cleared to continue driving.

The latest report on WCR comes just weeks after a second ban on its operations was lifted in by the ORR in March.

The watchdog had issued a prohibition notice in February following fresh concerns over safety, including an incident in Doncaster last October where staff on one of the company's locomotives had again turned off the TPWS system.

The ORR reinstated the licence on March 23, saying its safety concerns had been addressed.

A spokesman for the company said: "WCR have recently undergone a complete overhaul and restructure covering all aspects of its health and safety policy including the strengthening of its main board and senior management team.

"This has been carried out and completed to the satisfaction of the ORR."