The RMT says a series of industrial action will be taken by its members on the Southern Railway network.

The Rail, Maritime and Transport union announced an escalation of industrial action which will bring fresh travel chaos for hundreds of thousands of passengers.

The strikes will start on October 11 and will be held intermittently until December 8.

The union has held a series of walkouts in recent months in protest against changes to the role of conductors at Southern, which is owned by Govia Thameslink Railway.

RMT general secretary Mick Cash said: "Yet again our members are being forced to take industrial action in a bid to maintain a safe and secure service on Southern.

"Govia Thameslink and the Government have made it clear that they have no interest in resolving this dispute.

"Instead they have begun the process of bulldozing through the drive towards wholesale driver-only operation (DOO) without agreement and without any concern for the impact on safety, security and disability access.

"Last week there was a train derailment near Watford that involved two trains. The guards on both trains played a vital role in protecting the passengers and the trains in what were extremely frightening circumstances. If the train had been DOO and without a guard, the consequences would have been far worse."

Conductors are to take 14 days of strike action by not booking on for any shifts between:

• 00.01 on Tuesday 11th October and 23.59 on Thursday 13th October

• 00.01 on Tuesday 18th October and 23.59 on Thursday 20st October

• 00.01 on Thursday 3rd November and 23.59 on Saturday 5th November

• 00.01 on Tuesday 22nd November and 23.59 on Wednesday 23rd November

• 00.01 on Tuesday 6th December and 23.59 on Thursday 8th December.