Commuters are braced for chaos as workers on South Western Railway (SWR) begin a 27-day strike.
It comes after talks between the Rail, Maritime and Transport (RMT) union and SWR over a long-running dispute over guards on trains broke down.
The operator called the action “unnecessary”. It said “more than half” of weekday trains will run but the last services will be earlier than normal.
The union said the strike was “in defence of passenger safety”.
The RMT said SWR “point-blank refused” to show any serious movement at talks held at the conciliation service Acas.
General secretary Mick Cash said the union was “angry and frustrated that a set of proposals that would have guaranteed the safety-critical role of the guard at the point of despatch, and which would have cost the company absolutely nothing, have been kicked back in our faces.”
SWR said it has offered “a guard on every train, and a safety critical role for that guard.”
A spokesman said: “What we are not prepared to compromise on is the much-needed modernisation of the service with improved performance, safety and customer service that our new fleet of modern suburban trains will vitally deliver for customers.”
The operator released a revised timetable and said it would provide longer trains to increase capacity where possible.
SWR runs services between London Waterloo and Portsmouth, Southampton, Bournemouth and Weymouth as well as Reading, Exeter and Bristol. It also operates suburban commuter lines in south-west London, Surrey, Berkshire, and north-east Hampshire.
Strike days are as follows:
- From 00:01 GMT on Monday 2 December until 23:59 on Wednesday 11 December
- From 00:01 on Friday 13 December until 23:59 on Tuesday 24 December
- From 00:01 on Friday 27 December 2019 until 23:59 on 1 January