Trade unionists joined the largest strike seen in Britain for at least 30 years on Wednesday in protest over government plans to reform pensions. Xinhua visited picket lines across London, which included ambulance stations, hospitals, the Houses of Parliaments, and government offices. Outside St Thomas\'s Hospital, directly across the river Thames from the Houses of Parliament, nurses, cleaners and other hospital staff joined forces to man picket lines at all the hospitals main entrances. Dino Williams, Unison branch secretary at St Thomas\'s Hospital, explained to Xinhua that the unions did not want to harm patients. \"In planning this event. what we have tried to do is make sure that patient safety comes first ... We are here with a sense of integrity, which means if we were needed, irrelevant to what argument we have with the government, patients will always come first,\"he sai.d Samad Billoo, the branch secretary of the Unite union at the London Ambulance Headquarters control services, was on the picket line in the early morning, flanked by two dozen strikers handing out leaflets explaining the unions\' position to passers-by and waving union flags. Billoo said he was on the picket line because \"we are going to be paying more, working longer, and getting less in our pensions.\" He said ordinary union members could back another strike in frustration with the government unless better offers were put forward. He said, \"If the government does not change its mind we see a series of strikes coming through.\" Tom Mellish, from the Trades Union Congress (TUC) the umbrella body for unions in Britain, was one of the organizers of a demonstration that marched through the center of London and Trafalgar Square to a rally opposite the heart of government in the Whitehall area. Mellish, speaking as demonstrators gathered in the morning, said the demonstration, matched by others at regional centers across the country, \"was planned to attract eight to ten thousand demonstrators but could attract up to twenty to twenty five thousand\" because workers were angry and wanted to protest. In the event demonstrators were said to have numbered 30,000 and the march brought traffic to a standstill over the lunch and afternoon period over much of central London. Xinhua spoke to the leader of the largest union in Britain, Len McCluskey. His Unite union is the largest in the two countries of Britain and Ireland. McCluskey toured picket lines in central London to gauge support for the strike, and to meet strikers. \"Strikers had gone on strike as a last resort,\" said McCluskey, \" feeling there was no other way of protesting against the coalition\'s pension reform plans.\" \"This government has managed to get teachers, and doctors, care workers and nurses and ordinary decent members of the public out on the streets -- they should be very proud of themselves,\" he said. The leader of the Unison union Dave Prentis, the largest union in Britain with 1.3 million members, praised the strikers. He told Xinhua: \"I\'m really proud about what we have achieved today; hundreds of thousands of our members walking out to show their anger at what is happening to their pension schemes. These are decent women and men -- mainly women who provide our public services; they look after us in our hour of need, they are asking the public now to look after them.\"