Nurses, firefighters, teachers and prison officers joined over 150,000 protesters in huge demonstrations against the Government, loudly cheering calls for a 24-hour general strike.
Union officials and politicians, including Labour leader Ed Miliband, bitterly attacked the coalition's spending cuts, accusing ministers of being more interested in supporting millionaires than ordinary workers.
The events in London, Glasgow and Belfast passed off peacefully, although activists from the Disabled People Against Cuts (DPAC) group staged a sit-in and cut off traffic close to Hyde Park in the capital.
The TUC said the turnout was better than expected and sent a strong message to the Government about the unpopularity of its policies.
General secretary Brendan Barber said: "We are sending a very strong message that austerity is simply failing. The Government is making life desperately hard for millions of people because of pay cuts for workers, while the rich are given tax cuts."
Mr Barber said the resignation of chief whip Andrew Mitchell and Chancellor George Osborne travelling in a first class train carriage with a standard ticket showed how out of touch the Government was.
He said: "The Chancellor eventually paid for his ticket, but the rest of us are paying the price for his disastrous policies."
The biggest cheers of the day came when Bob Crow, leader of the RMT rail union, and Mark Serwotka of the Public and Commercial Services union called for a general strike.
Mr Miliband dubbed the Prime Minister "clueless" and said he was "clinging" to policies which were not working.
He said the coalition was cutting taxes for millionaires and raising them for everyone else, but he was booed by a small section of the crowd when he said Labour would have to make "hard choices" if it was in Government.