Train drivers union Aslef will ballot its members over industrial action against Southern Railway after the last round of talks between the union the the train operator Govia Thameslink Railway (GTR) failed to resolve their dispute about the role of guards and driver-only operated trains.

"We have genuinely sought to reach a compromise with Southern," said general secretary Mick Whelan. "We have always been prepared to talk to the company, and we have always been of the view that it is, or should be, possible to do a deal – as we did with ScotRail –­ but it takes two to tango and the company has not been prepared to negotiate. They want to impose, not to discuss. They have dug in their heels and forced us to ballot our members."

The union will send out ballot papers to its members on Friday 4 November to be returned by Friday 18 November. This could mean the beginning of a new series of strikes against the embattled GTR.

A 72-hour industrial action called by National Union of Rail, Maritime and Transport Workers (RMT) against Southern started on Tuesday, following on from another three-day strike last week which left the company running its services as 61% capacity.

GTR offered £2000 bonus in exchange for acceptance of its driver-only plans, but the union rejected the offer as a "bribe", saying the safety of passengers and staff "is not for sale". RMT is organising a rally outside Parliament on 1 November and is ready to call a new series of 72-hour strikes over November and December.

Appearing before the Commons' Transport Select Committee to detail his priorities on Monday, Transport Minister Chris Grayling said the government will not get involved in the dispute. He also excluded stripping GTR of its franchise, despite a recent report from the committee showing that Southern had breached its contract and that ministers had failed to monitor the firm.