Thousands of people are expected to join a huge protest at Labour's annual conference against public spending cuts as well as anger over the UK's continued involvement in the conflict in Afghanistan.
A coalition of trade unions and anti-war and anti-fascist groups have teamed up to hold a demonstration to mark the opening of the conference in Brighton.
Activists will complain that the continued deployment of troops in Afghanistan and Iraq, together with the proposed replacement Trident nuclear programme, cost billions of pounds that could be spent on jobs, education and public services.
The theme of the protest is to prioritise spending on public services rather than war or weaponry.
Sally Hunt, general secretary of the University and College Union, which is involved in the demonstration, said: "The rally should act as a wake-up call to all politicians. Making cuts to the public sector is not the way ahead for this country. Reducing investment and sacking educators during a recession is an act of academic vandalism.
"Where will the next generation of doctors, nurses, engineers and social workers come from if not universities? Who will provide the opportunity for unemployed people to learn and retrain if not colleges? The prime minister has rightly said that education is the key driver to get Britain out of recession. Now is the time for him and the government to put their money where their mouth is and invest in our colleges and universities rather than make cuts."
Mark Serwotka, leader of the Public and Commercial Services union, will say: "The main political parties have forged a damaging consensus on public sector cuts when it was the greed of the City that caused the financial crisis. Bumper bonuses are back for the self proclaimed 'masters of the universe' whilst the ordinary tax payer foots the bill and political parties sharpen the knives to cut public services to pay for bailout of the banks.
"A smokescreen has been thrown up and divisive myths about civil and public servants voiced to create divisions between public and private sector workers. We oppose false divisions. The real issue is the injustice of making the low paid, wherever they work, pay for a crisis not of their making. It is the millions of ordinary taxpayers who rely on public services who will bear the brunt of public service cuts."
The Stop The War Coalition will also have supporters at the protest, renewing their call for British troops to be withdrawn from Iraq and Afghanistan.
Coaches have been booked from across the UK to transport activists to the lobby from areas including Plymouth, Exeter, Manchester, Leeds, Cardiff, the Midlands and Scotland.