More than 200 engineers at Southern Rail are to be balloted for possible strike action over claims that industrial relations have "comprehensively broken down".

Members of the Rail, Maritime and Transport union at Southern will vote in the coming weeks on whether to mount a campaign of action over issues including new rosters and working conditions.

The union is also seeking a four-hour cut in the working week to 35 hours.

RMT general secretary Mick Cash said: "RMT will not stand by while agreed policies, procedures and agreements are unilaterally ripped up by Southern and as a result we are now in dispute.

"Southern is a company intensively under the spotlight over its performance at the moment and RMT will not have our members scapegoated for failures at the top by outrageous and intimidatory demands to meet impossible work targets and through attacks on working conditions.

"The union is in no doubt that the pressure on these staff to deliver impossible targets compromises safety in what is clearly a safety-critical environment."

The new wave of possible industrial action comes soon after Southern Rail fended off strike-threats from ASLEF, the train drivers' union, by making an improved pay offer to its members.

A spokesman from Southern Rail said: “We are aware of the issues the RMT have in our engineering department and dialogue with the union is ongoing. We have received no formal notification from the RMT that it intends to ballot its members. Until we understand the exact details of any potential ballot we are unable to comment further.”