For one rail passenger it was like being ‘held hostage’. Another compared conditions in her carriage to an oven. Stranded for up to five hours, they endured discomfort, frustration and danger more associated with travel in the Third World. In fact they were among thousands on two commuter trains near Clapham Junction – Britain’s busiest interchange station – during morning rush hour as services descended into chaos. Scroll down for video . Chaotic scenes: Thousands of commuters were stranded on trains for up to five hours after a power failure at Clapham Junction station (pictured) in south-west London . Heat: Sami Dodangeh tweeted a picture of police officers handing out water to passengers in stifling conditions . Fire crews help passengers down from the 7.02am East Grinstead to Victoria service which was stranded for four hours . Firefighters used a ladder to help passengers get to safety after some 1,200 people were stuck on the East Grinstead to Victoria train a quarter of a mile south of Clapham Junction . Waiting game: London Victoria station earlier this evening after a power cut in led to severe delays . Extremely busy: MailOnline reader Junior Imode sent in this picture of queuing at London Bridge station earlier tonight, at the entrance to the Jubilee line on the London Underground . Assistance: Staff were on hand to help passengers facing a difficult journey home from London Victoria . Furious passengers were stuck between stations in South London after a power supply problem led to four lines being closed. On platforms, fights broke out when trains did arrive as passengers pushed their way through the doors. Police boarded the stranded trains to hand out water, and paramedics were on hand in case travellers, including pregnant women, were affected as the crowded carriages became unbearably hot. Passengers were not allowed to leave the trains by themselves due to safety concerns. As the chaos unfolded across the network, there were at least 338 cancellations and 138 part cancellations that either missed stops or terminated before their destination. In all, 321 trains were delayed for a total of more than 600 hours. Some 1,200 people on the 7.02am from East Grinstead to Victoria were evacuated from the train after it was stuck for four hours a quarter of a mile south of Clapham Junction. Firefighters used a ladder to help them down before they were led along the track to safety. British Transport Police started evacuating passengers on the stranded service at 10am and passed water to others trapped on board with no air conditioning. Emergency services: British Transport Police officers began evacuating stranded train passengers to waiting buses at around 10am and water was passed through to others still stuck in sweltering temperatures on board . Aid: Fire officers help a man disembark from the  stranded 7.02am service to London using a makeshift ladder . Helped off: One train carrying more than 1,200 passengers between East Grinstead and Victoria was evacuated . PC James Vernon, 40, was one of the 900 passengers rescued and admitted conditions on board were 'horrendous'. A planned strike by rail workers on Bank Holiday Monday in a dispute over the sacking of a colleague has been called off. Members of the Rail, Maritime and Transport union on East Coast trains based at Edinburgh's Waverley station were due to walk out for 24 hours. The union said the dispute had been resolved and the sacked employee has reached a 'satisfactory settlement' with the company. He said: 'It was absolutely stifling on board the train, it was horrendous. There was so much mis-information about what was going to happen. 'When they decided we were going to be evacuated, we had to wait for everyone to go down two metal steps and go one person at a time along the railway line.' Around 1,000 passengers on the 6.56am from Brighton, East Sussex – also a Southern Rail service – were stranded for nearly five hours. The train should have reached Victoria at 8.15am, but it was finally towed into Wandsworth Common station just before 1pm. One of its passengers, student Hannah Phillips, 20, from Eastbourne, East Sussex, said: 'I was lucky that I was carrying a bottle of water with me as it was getting very hot on the train. 'This is probably the worst train journey I've experienced.' Walking off: Commuters on board the stranded 7.02am service took photographs of the evacuation process . Stranded: Up to 2,000 commuters were eventually led along tracks onto rail replacement buses today . Another passenger on the held-up Brighton train was Ben Goode. He tweeted: 'This is a shambles.' As the service went into meltdown, with the Gatwick Express unable to run and office workers hours late for work, tempers frayed among passengers on platforms. 'Brighton train on, Brighton train cancelled, on, cancelled etc. Not having fun heading from Lndn. Network rail is a shambles.' - Donna Burtchaell . 'I used to work for a train operator so understand but today was a shambles....' - Chris Scott . 'I see Network Rail are making peoples lives a misery again, stuck on trains outside Clapham for four hours, railway in this country, joke.' - Johnny Wishbone . 'Network rail get us off this train and let us walk to clapham! We've been here nearly 2 hours and taking us to Wandsworth is a joke!' - Katie Glaysher . 'Train 28 minutes late....missed 2 connections but Network Rail don't think that's worthy of any compensation.' -Victoria Slater . One tweeted: ‘Absolute chaos @ #Claphamjunction. Fighting to get on trains, falling down gap between train & platform. It’s dangerous.’ Anna Roberts, a journalist on the Brighton train, reported: ‘It’s been nearly four hours now. Police and paramedics boarded because there is no air conditioning. 'They were bringing water. With the power off, it’s like an oven. Police said it’s too dangerous to walk down the track.’ Another passenger tweeted: ‘I’m being held hostage by @SouthernRailUk. There are hundreds of us packed in sweaty carriages. No demands have been made yet.’ Veterinary student Farid Rahman, 19, who was on the evacuated train, said: ‘After three hours the fire brigade came and everyone was evacuated one by one from one door – so the process was lengthy.’ The cause of the power failure was being investigated last night amid claims by railway staff that it could have been down to work done by Network Rail the night before. A broken third rail – which supplies power from the track to the trains – led to the mayhem by disabling the trains’ ‘shoe’, which conducts the power. The chaos came after Sir Peter Hendy, transport chief for London, said commuter services into the capital were appalling, with ‘Gestapo’ ticket inspectors and ‘Wild West’ conditions. Single file: The problem struck between Wandsworth Common and Clapham Junction in the middle of the morning rush hour. People are pictured being evacuated from one of the trains . Discussion: Hundreds of people took to social media to vent their frustration and Freya Richard posted this picture with the caption: 'How many people does it take to make a decision'
Power failure sparked a 'total meltdown' on London trains across the day .
Thousands of passengers stranded on two trains near Clapham Junction .
Police boarded trains to hand out water and paramedics had to be on hand .