Guards on Southern Railway are to stage a fresh strike in the long-running dispute over staffing and driver-only trains.

Members of the Rail, Maritime and Transport union (RMT) will walk out for 24 hours on August 1, coinciding with the first of three strikes by drivers.

The RMT called the new strike because of the "total failure" of the Government and Southern's owners Govia Thameslink Railway to try to resolve the year-long dispute.