Mr Ambrose and other angry passengers have set up a protest group, More Trains Less Strain, and are planning a fares strike over the decision by First Great Western (FGW) to withdraw 20 carriages.

The company, which has by far the worst punctuality record in the country, with more than a quarter of trains late, is saving £100,000 per carriage in annual leasing and maintenance costs by sending them into so-called warm storage at Eastleigh in Hampshire.

It has cut trains in half, leaving dozens of stations in Somerset and Wiltshire with services made up of only one or two carriages even though people had been struggling to find seats on the old four-carriage services.

FGW has also cancelled more than 700 services in the past four weeks, mainly because of a shortage of trains.

Hundreds of passengers at Bath, Trowbridge, Keynsham, Bradford-upon-Avon and Salisbury are being left stranded on platforms, unable to squeeze on to trains that arrive already dangerously overcrowded. A fortnight ago a passenger fell into the gap between the train and platform at Bath Spa station as people surged towards the doors. Several other passengers have fainted on packed trains.

Train guards are frequently demanding that people get off and wait for the train behind, which turns out to be equally overcrowded.

Commuters from Maidenhead, Twyford and other stations in the Thames Valley are also enduring severe overcrowding, with many having to abandon their journeys, because FGW has introduced a new timetable that favours more profitable long-distance trains.

This week FGW tried to pacify passengers around Bristol by borrowing all the carriages from the St Ives and Looe branch lines in Cornwall. But this has created a separate outcry from Cornish passengers, who have had to travel on buses.

The RMT union, which represents train and station staff, has complained that its members are being abused by frustrated passengers.

FGW is one of a growing number of rail companies struggling to reconcile sharp cuts in subsidy from the Government with a record growth in demand. More than 1.1 billion rail journeys were made in Britain last year, the highest number for 50 years. Last year FGW signed a new ten-year franchise deal under which it not only agreed to cease receiving a subsidy but committed itself to paying the Government a premium of £1.1 billion.

More Trains Less Strain is holding a meeting on Tuesday in Bath at which it will announce a campaign of direct action, including a day when passengers will refuse to buy tickets or show passes.

Mr Ambrose, a charity worker from Bath, said: “Why should people pay for such appalling treatment? The service has collapsed in recent weeks and it has become a lottery whether you will be able to get on a train.

“Even First’s staff are on our side — they can see the madness of storing trains in sidings when record numbers of people want to travel by rail.”

Caroline Copeland, a teacher from Oldfield Park near Bath, said that she had been late for a work three times in a week because the trains had been too crowded when they arrived. “Unless you are standing right beside the door when it stops, you have no chance of squeezing on.”

Theresa May, the Shadow Leader of the House and MP for Maidenhead, called for FGW to be stripped of its franchise. “They are making a shambles of the service, with people abandoning trains and going by car and even talking of moving house to avoid the nightmare of rail travel,” she said. “It is partly the Government’s fault because it specified a reduced service to the bidders for the contract.”

FGW said that the shortage of trains was being exacerbated by mechanical problems with the remaining fleet. A spokesman said that the company had agreed the reduction in carriages with the Department for Transport as part of its contract.

The department denied that it was to blame and said that it had been up to FGW to decide how many carriages it needed.

Alison Forster, FGW’s managing director, met a group of MPs including Ms May at Westminster yesterday to discuss the problems. She said that some extra services would operate from Monday.

She added: “We recognise that some elements of the timetable have not met all our customers’ needs and we apologise to those who have experienced crowding and train cancellations on some key services.”

Tales from the commuter line

• “My train home on Tuesday was packed like the worst Tube train. The guard announced that, for health and safety reasons, people had to get off and wait for the next train. Some did, only to find the next service was also only two carriages and absolutely packed”

  Simon Carpenter, 52, health trust worker from Frome

• “I waited 75 minutes at Oldfield Park station on Wednesday. Two trains came in, but they were so crowded only a few people managed to squeeze on. Coupled with this, I bought my monthly season ticket on Monday and it had gone up from £99.65 to £111.80 — that’s a 12 per cent increase”

  Jane Roberts, 49, college lecturer from Oldfield Park

• “It has been so crowded on board recently that it becomes unbearably hot and you can't even turn your shoulder. My train used to be four carriages but now it's only two”

  Kelly Horton, 32, fund- raising manager from Bath

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