Talks aimed at averting strikes on Southern Railway have broken down leaving tens of thousands of passengers facing a week of "misery."

The company spent three days meeting with the Rail, Maritime and Transport union under the chairmanship of the conciliation service Acas but they failed to resolve a bitter dispute over the role of conductors.

Union members will now strike for five days from next Monday, causing travel chaos.

The company's passenger service director Angie Doll said: "We have gone the extra mile with our compromise offer but the RMT has made it clear they are not prepared to negotiate.

"They did not want to discuss the role of the on-board supervisor and remain rigidly opposed to evolving the role of on-board staff to focus more on customers.

"We are deeply disappointed and angry on behalf of our passengers at this stance, which will cause misery for our passengers and untold damage to the local economy in the South East. The RMT's strike is unnecessary, unacceptable and unjustified.

"We plan to have just as many services staffed with on-board supervisors as we do with conductors today. We simply want the flexibility to be able to run a train without a second member of staff on board, if they are unavailable, so we can get our passengers on their way.

"To provide assurances that we would do this only when absolutely necessary, we said we'd agree with the RMT a list of binding rules to dictate when this could happen - such as during severe disruption. Their refusal to even discuss this demonstrates their complete unwillingness to compromise.

"Our proposals match modern-day customer service to modern-day trains. The only difference is drivers will close the doors, freeing up our on-board staff to provide the best customer service. Our on-board supervisors will also be able to work on any service, which means more efficient working and fewer cancellations for our passengers."

Southern, part of the huge Govia Thameslink Railway franchise, said an offer by the union to suspend industrial action if the company agreed to terms put forward by ScotRail to resolve a separate dispute, was a "complete red herring".

Ms Doll said: "This amounts to a continuation of the current operating model and delivers none of the punctuality and customer service benefits we are determined to deliver to our passengers."

The RMT claimed the talks had been "sabotaged" by the Government.

General secretary Mick Cash said: "It was clear right from the start of these talks that there was no serious intent from Govia Thameslink to engage in genuine negotiations, and that their script was being written from behind the scenes by their government paymasters.

"You would have thought they would have taken our arm off when we offered to suspend the action in return for a series of guarantees that simply mirror the proposals from ScotRail just a couple of a few days ago.

"I have been involved in countless negotiations and have never witnessed a farce like this.

"Our action in defence of rail safety and the safety critical role of the guard now goes ahead next week and passengers caught in the middle of this wrecked process will be rightly furious that talks that could have resolved this issue were sabotaged.

"Compared to the progress we have been able to make on ScotRail it is clear as day that GTR is being set up as a testing ground for a national union-busting experiment.

"That nonsense should be stopped right now and we should be allowed to get back to normal industrial relations, free from outside interference."

The union said it was told by industry sources that Transport Department official Peter Wilkinson, who told a public meeting he wanted a "punch up" with rail unions was responsible for "wrecking" the talks.

He was accused of "calling the shots from behind the scenes".

Mr Cash said: "Passengers will be well aware that Mr Wilkinson commutes from Vienna and is paid £280,000 a year as a Government hit man.

"Our members refuse to cave in to his bullying and intimidation and will be standing firm. He made it clear in his infamous Croydon speech that he intends to starve our members back to work.

"It's that aggressive and provocative attitude that has blocked all attempts to resolve the Southern dispute."

Announcements were made at railway stations warning passengers that the strikes are going ahead.

Southern said it will run 60% of trains in an emergency timetable from Monday. Some routes will have no services.

An Acas spokesman said: "After three days of talks at Acas, Southern Railway and RMT have been unable to reach agreement in respect of their dispute on the role of conductors.

"There are no plans for further talks at the moment but the parties are aware that our services remain available to them."