Southern rail has set a new record low for customer satisfaction with the trains’ toilets among the only two things to receive a score above rock-bottom.

A report published today gives the Southern service a satisfaction rating of just 21 per cent, the poorest result of any operator in the history of the Which? survey.

Southern was given the lowest-possible one-out-of-five stars in all categories but two - the condition of its toilets and its carriages - where it got two stars.

Southern accepted that “performance is unacceptable,” and apologised, while the RMT union said the the company was “the absolute worst of a bad bunch.”

Consumer survey firm Which? polled 2,218 train users in October and November, including 256 Southern commuters.

Respondents were asked to award stars and points for punctuality, reliability, seat availability, standing space, frequency, the conditions of the carriages and the toilets, and value for money.

Merseyrail and Virgin West Coast received four or five stars in every category, with scores of 72 and 69 per cent.

At the bottom of the table, Southern got one- or two-stars and the record low score of 21 per cent. Thameslink and Great Northern, also owned by Govia Thameslink, ranked third-from-bottom of the 21 operators with 32 per cent.

Vickie Sheriff, Director of Campaigns and Communications at Which? said: “After months of disruption, it’s no surprise to see Southern at the bottom of our customer satisfaction survey.”

A spokesman for Which? said a direct comparison with previous years and other operators is difficult because of changes to the survey and samples, but said this was the lowest score ever received in the six years of the project.

A spokesman for Govia Thameslink said: “Performance is unacceptable and we’re sincerely sorry. Our passengers deserve better and, together with Network Rail and its £300m funding package to improve track signalling and overall performance, we’re working hard to improve the service.

“This survey inevitably reflects the significant impact of the wholly unjustified industrial action being taken by Aslef and the RMT.”

RMT leader Mick Cash said: “This Which? Report shows that Southern Rail are the absolute worst of a bad-bunch when it comes to Britain’s rotten, privatised railways. The responsibility for this catastrophic mismanagement of this crucial rail operation lies fairly and squarely with the Government and their contractors GTR.”

He went on: “GTR and their French-backers, who routinely put private profits before passenger services and safety, must be stripped of this franchise with the public sector given a chance to sort this mess out once and for all.”