More dates for strike action by workers on South Western Railway have been announced in the dispute over the role of guards on trains.

Members of the Rail, Maritime and Transport (RMT) union will walk out for two 24-hour periods from 10am on March 9 and March 12.

It is the sixth time SWR staff have voted for industrial action in the long-running row.

Passengers suffered weeks of travel misery when RMT members went on strike for 27 days during December, leading to thousands of services being cancelled.

RMT general secretary Mick Cash claimed its members had "no choice" but to vote for strike action, and accused SWR of attempting to intimidate workers with a "barrage of lengthy letters".

He went on: "RMT will not tolerate our members being bullied or intimidated by any company at any time, whether we are in dispute or not.

"I want to congratulate our members on their continued resolve in their fight for safety and the role of the guard on SWR.

"It is wholly down to the management side that the core issue of the safety critical competencies and the role of the guard has not been agreed.

"The union remains available for talks."

An SWR spokesman said: "We are disappointed that the RMT has chosen to announce further strike dates, particularly as we already have further talks planned.

"After a month of strikes last December, we hoped the union would realise that talking, not striking is the only way forward.

"While we have compromised on a number of points since this dispute started, SWR is the only suburban network within London with guards still operating the doors.

"We have guaranteed to keep a guard on every train, but it is vital that we use the most efficient means of dispatch when we introduce our new trains so that we can deliver the improved performance our customers so desperately need.

"Passengers will rightly question whether the RMT really wants to find a solution to this dispute.

"We will do everything possible to keep our customers moving."