A series of nationwide protests were being held by workers, union activists and campaign groups to warn of the threat to jobs and public services as a result of the Government's spending cuts.
Public sector workers including nurses, teachers, librarians, firefighters and other employees will take part in rallies and meetings as part of a campaign against the Comprehensive Spending Review.
Events were being held in areas including Cardiff, Newcastle, Sheffield, Barnsley, Cambridge, Southampton, Bolton, Luton and London.
American civil rights activist Jesse Jackson was to join a protest in Westminster called by groups including unions and the Stop The War Coalition.
A march will be held through Dorchester, Dorset, led by a coffin and a hearse, with protesters wearing black to symbolise the "death" of public services.
Further demonstrations will be held in the next few days and the TUC is organising a national protest in London next year.
The TUC said up to 3,000 people from across the UK joined a protest in Westminster on Tuesday, 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.
"If the Government doesn't listen to us today, they won't have heard the last of us. If George Osborne's cuts go through - cuts that could mean a death sentence for our services and our communities - then we will be back."