Passengers travelling with the majority of Britain's train operating companies are dissatisfied and would not recommend their service, a survey by the consumer group Which? has found.

The survey of more than 7,400 regular passengers produced satisfaction scores of 50% or less for 11 out of 19 train operators surveyed. Bottom of the table were Greater Anglia and Southeastern, which run commuter services out of London, with the most satisfied customers travelling on Merseyrail, a self-contained network around Liverpool. The best scores for commuter trains went to National Express's C2C line, with Virgin topping the long-distance table, and beleaguered First Great Western rated the worst.

Eight in 10 passengers believed fares were too high, and one in five commuters said they had been forced to stand on their last journey. First Capital Connect and Greater Anglia rated lowest for cleanliness among commuters. More than one in 10 passengers said toilets were not in good working order. While only a quarter of passengers who felt they had cause to complain on their last journey had done so, those that had complained were mostly dissatisfied with the outcome.

The executive director of Which?, Richard Lloyd, said: "It's disappointing to see some train companies consistently falling down on the basics of customer service, with dirty and overcrowded carriages and toilets that don't work.

"Seven rail franchises end in the next two years and we want to see passengers' experiences put right at the heart of the tender process so companies respond to consumer expectations and can be held to account if they don't."

The Which? scores are markedly lower than the passenger satisfaction results collated by the watchdog Passenger Focus from a far bigger sample. However, Which? said its scoring system, based on overall satisfaction and likelihood to recommend a company, used the same criteria it employed for other markets. Respondents were polled in early January, soon after the latest price rises.

The Rail Delivery Group said: "As we acknowledged last month when the independent watchdog found that more than four out of five passengers were satisfied with their overall journey, the industry needs to build on the improvements it has delivered over the last 15 years.

"We are always keen to get feedback from customers, whether good or bad, which has helped the industry attract record numbers of passengers and cut complaints by three quarters in a decade."

Bob Crow, leader of the RMT transport union, said the survey showed that Britain's privatised railways "are delivering lousy service to the public while money that could be invested in capacity and upgrading is siphoned off into multi-million pound profits for the rich.

"Boris Johnson should take note of the fact that the British people want ticket offices and properly-staffed stations which was the issue at the heart of the Tube dispute."

The rail minister, Stephen Hammond said: "As well as getting passengers to their destinations, operators should be working hard to improve the overall experience of their customers. Passengers have every right to expect trains to arrive on time and be clean, and while this can be a challenge, I expect operators to do all they can."