Image copyright Getty Images Image caption Staff shortages and industrial action over the role of conductors have caused months of disruption on the Southern network

A Southern rail boss has admitted adverts urging passengers to tell the RMT union how they felt about ongoing strikes were a mistake.

In October Southern tweeted: "Time to get back on track. Tweet @RMTunion & tell them how rail strikes make you feel."

Dozens of passengers immediately responded by criticising Southern.

The union's leader Mick Cash said it was shocking Southern had spent money "bullying" its own staff.

The latest strike in the long-running dispute over the role of conductors on trains is due to start at midnight.

Image copyright TWITTER/SOUTHERN Image caption This tweet on 3 October led to some detailed feedback from passengers

Alex Foulds, deputy chief operating officer of Govia Thameslink Railway, which owns Southern, was questioned by councillors in the London Borough of Lambeth.

Mr Foulds said the adverts were a "mistake". He said the relationship with the RMT was "very tense" and the union had also made mistakes during the dispute.

He also apologised for the level of service being provided by Southern after months of industrial action by the RMT and high levels of staff sickness hit train services between London and Surrey, Sussex, Kent and Hampshire.

Mr Foulds said: "This has made it very difficult to run a reliable service."

'Scandalous'

Lambeth Labour councillor Ed Davie said it was "absolutely shocking" the company would spend tens of thousands of pounds on adverts calling on its customers to attack the union.

Jennifer Brathwaite, member for environment and transport on the Labour-run council, said: "The service provided by Southern is nothing short of scandalous.

"London's mayor agrees, as does nearly every other local authority affected by Southern's abysmal service, so we need the government to stop dragging its feet and put in place a clear plan for this franchise to be transferred as soon as possible."

Image copyright Twitter Image caption Many people replied criticising Southern and supporting the RMT and its members

Mr Cash, the general secretary of the RMT union said staff had been "set up for abuse and assaults" by the ad campaign.

He said: "It is shocking that hundreds of thousands of pounds of fare payers money has been wasted by Southern on attacking and bullying their own staff.

"That money could have been invested in keeping guards on the trains and keeping the public safe."

Members of the drivers' union Aslef on Southern are currently voting on whether to go on strike in a row over the driver-only trains.

RMT strike dates: