RAIL firm Northern has admitted using replacement staff during its increasingly bitter industrial dispute with the RMT union.

The company said about a hundred staff normally carrying out other jobs took over conductor duties while RMT members on Wednesday walked out for 24 hours – the latest in several strikes on Northern which have now reached double figures.

The RMT said the action, prompted by a row over driver only trains, was again “solidly supported”.

Its general secretary Mick Cash stated passengers were being placed at “greater risk because rail bosses have trained an army of managers and inexperienced backroom staff to replace highly trained and experienced guards in a bid to break the strike action”.

He said: “It is obvious to anyone that this will mean passengers will be more at risk, yet the rail safety regulator is not intervening to protect passengers.”

A spokesman for Northern rail, which is managed by Arriva, said more than a hundred Northern colleagues had been fully trained to carry out conductor duties to help run more than 1,350 services during the latest strike.

He said: “We are concentrating our efforts on getting customers into work and home again and can assure the public we do not compromise on safety.

“The rail industry’s independent safety regulator has approved our approach.”

RMT members on Southern, South Western Railway and Greater Anglia were on strike on Wednesday and Thursday while a 24-hour walkout went ahead at Merseyrail and Northern on Wednesday.

Despite some inevitable disruption for passengers, the Department for Transport said the large majority of trains in the affected areas had been running.