Gatwick Express, Southern and Thameslink staff are to be balloted on new strikes in a long-running national rail dispute over pay, job security and conditions.

The TSSA union will ballot its "hundreds" of Govia Thameslink Railway members later this month; the ballot will open on Wednesday 28 September and run until Wednesday 19 October.

If members vote in favour of strike action, walkouts could be called in early November – as early as 14 days after the ballot closes, if it is successful.

Govia Thameslink operates Gatwick Express and Southern, which both serve Gatwick; it also operates Thameslink, which serves both Gatwick and Luton. The network operates services from Cambridge, Bedford, Brighton and the south coast to central London.

The group’s members include platform staff, ticket office staff, train crew, engineers, control, administrative staff and management.

Manuel Cortes, TSSA general secretary, said the union’s GTR members were concerned about mounting cost of living pressures, and urged them to vote in favour of both strike action and action short of a strike.

"We know we are in a fight for the future of our railways," he said. “We have already seen a strong set of ballot results elsewhere in rail companies our union represents, and we are ready to take strike action again in the coming weeks."

Cortes urged GTR to come to the negotiating table or risk "crippling" strike action on one of the UK’s main rail networks.

TSSA members are seeking a pay rise which meets the rising cost of living; a no compulsory redundancy agreement for 2022; and no un-agreed changes to terms and conditions.