Thousands of health workers, council staff, firefighters, teachers and other public sector employees have joined a noisy rally in Westminster to protest against the Government's "brutal" spending cuts.
They cheered speeches from union leaders, a 14-year-old schoolgirl and Sherlock Holmes actor Benedict Cumberbatch before lining up to lobby MPs about the threat to jobs, pay, pensions and services by Wednesday's comprehensive spending review.
Unison claimed Conservative MPs attended a hastily arranged meeting with Prime Minister David Cameron to avoid meeting the demonstrators.
The TUC said up to 3,000 people from across the UK joined the protest, with 2,200 packing into Westminster Central Hall, hundreds outside unable to get in and several hundred more queuing up to meet their local MP in Parliament.
Dave Prentis, general secretary of Unison, said: "The coalition is taking a chainsaw to our public services and we are under attack, not because of a deficit, but because of an ideology. We will build an alliance of all public service unions to break the pay freeze, protect our pensions and stop the cuts."
Mr Prentis branded Tory MPs as "cowards", adding: "I am outraged that Tory MPs have turned their backs on their constituents, when so many have travelled hundreds of miles, to see them.
Lizzie Louden, a 14-year-old pupil of Leytonstone School in East London, said students had been looking forward to improvements to buildings before the Government cancelled the Building Schools for the Future scheme. She said she was "angry" at the decision, complaining that some buildings contained asbestos, while pupils refused to use the toilets because they were in such a "terrible" state.
Mr Cumberbatch, representative of the actors union Equity, said he did not want to perform in front of only "Tory sons and daughters" if arts funding made it too expensive to watch live theatre. The arts was a profitable industry, creating world famous films and plays, he said, warning that cuts of 25% would make a "massive difference".
TUC general secretary Brendan Barber said the Government's cuts programme was a political choice, not an economic necessity, that would make Britain "a more unequal, more squalid and nastier country".
Unite's joint leader Tony Woodley said that for every four public sector jobs forced out by Government, three more would follow in the private sector.