Protest march against coalition cuts expected to attract 300,000

More than a quarter of a million protesters against public sector cuts are expected to flood central London today in the biggest political demonstration for nearly a decade.

Police sources, normally cautious about estimating numbers, said last night they were braced for up to 300,000 people to join the march – far higher than previous forecasts from TUC organisers.

More than 800 coaches and at least 10 trains have been chartered to bring people to the capital from as far afield as Cornwall and Inverness.

The Metropolitan police, under fire for their use of kettling in previous protests, said "a small but significant minority" plan to hijack the march to stage violent attacks. Organisers, however, insist it will be a peaceful family event. Union members are expected be joined by a broad coalition, from pensioners to doctors, families and first-time protesters to football supporters and anarchists.

Ed Miliband said the government was dragging the country back to the "rotten" 1980s. Labour is calling today's event the "march of the mainstream".

The opposition leader will address the rally – his biggest audience ever – in Hyde Park to set out Labour's alternative to the cuts, accusing the government of fomenting the "politics of division" not seen since Margaret Thatcher's 1980s.

His remarks are reinforced by a Guardian/ICM poll that shows the public divided over the cuts. Of 1,014 people questioned this week, 35% believe the cuts go too far, 28% say they strike the right balance and 29% say they don't go far enough; 8% don't know.

Two other polls put the balance more strongly against cuts. A YouGov survey for Unison found that 56% believe the cuts are too harsh and a ComRes poll for ITV showed that two-thirds think the government should reconsider its planned spending cuts programme. Just one in five disagree with that view.

The TUC organisers of the event said they had organised a family-friendly demonstration with brass, jazz and Bollywood bands. But with unofficial feeder marches, sit-down protests and a takeover of Trafalgar Square planned, there was increasing nervousness that acts of peaceful civil disobedience could lead to stand-offs with police and outbursts of violence.

Shami Chakrabarti, director of Liberty, which is providing 100 legal observers along the route to monitor the scenes, said she had been heartened by advance co-operation between the TUC and police, but added: "Events around in the world show the precious nature of peaceful dissent guaranteed by our Human Rights Act. This fundamental freedom was hard won and is still much envied elsewhere. It must not be jeopardised either by over-zealous policing or anyone looking for trouble."

Miliband said in a speech in Nottingham: "I thought the politics of the 1980s were rotten because they divided our country. I fear that this government is practising the politics of division."

He argued that the government's policies divided rich against poor, public sector workers against private sector workers and north against south. "These aren't the voices of people marginal to our country but the voices of the mainstream majority in our country and that's why I'll be addressing the rally tomorrow," he said. He had been told not to join the march because of safety concerns.

The Tories called on Miliband and the TUC leader, Brendan Barber, to take responsibility for any disruption on the march. Michael Fallon, deputy chairman of the Conservative party, said: "Under Ed Miliband, Labour are abandoning the centre ground, retreating into their comfort zone of left-wing protest and cosying up to the unions."

Barber will tell the rally that no part of the public realm is protected from the cuts, highlighting the proposals to radically change the NHS. "Today let us say [to David Cameron]: we will not let you destroy what has taken generations to build," he will say.

The bulk of the march will be made up of trade unionists, with virtually all of the TUC's 55 affiliated unions represented. Also among the marchers will be a coachload of mothers and toddlers from Hampshire demonstrating against the closure of Sure Start centres in the county.

Catherine Ovenden, 31, said the decision to cut the service would have a devastating impact on families. "So many people rely on these centres and we are going to lose a third of them," she said .

The demonstration is timed to mark the new financial year next week, when many of the cuts kick in. Research by the Fabian Society suggests that taken with the wider tax and benefit reforms announced since the election, this week's budget would in fact force large number of working families into tax, instead of lifting them out as the coalition has claimed.

Tens of thousands of the lowest-income families will lose around 6% of their net income in the next year because of the government's tax and benefit changes with the bulk of the cuts kicking in next week, the analysis by the Fabian Society shows. From next week the childcare element of the tax credit system will be reduced from 80% to 70% of qualifying families' nursery bills. A family with one child and one earner earning up to £23,000 will lose between 5.7% and 6.4% of their net income, compared with last year. This would cost such a family with an income of £6,000 £1,362 a year and a family on £23,000 £1,710 a year.