Thousands of students headed to London Wednesday to march against cuts to higher education funding, as a huge police operation sought to head off any repeat of violent protests one year ago.

Scotland Yard has deployed 4,000 officers to police the demonstration against cuts to university funding and a hike in tuition fees, which organisers expect about 10,000 students to attend.

Police have been authorised to use plastic bullets if there is any repetition of last year's violent demonstrations, which kicked off with an attack on Prime Minister David Cameron's party headquarters on November 10.

The university students are planning to march to the City of London financial district, passing close to St Paul's Cathedral, where anti-capitalism protesters have been camping out since mid-October.

Police have insisted they do not believe it was "inevitable" that the protest would descend into the violence of a year ago when students ransacked the lobby of the tower block housing the Conservative party's offices.

"We know the overwhelming majority of students are law abiding and we hope this will be a peaceful event," Metropolitan police Commander Simon Pountain told a press conference earlier this week.

"We certainly don't see it as inevitable that we will witness a repeat of last year's scenes of violence and criminal damage.

"However, it would be negligent if we did not plan a response to the small minority who may be intent on disruption and may not intend to be peaceful."

March organisers, the National Campaign Against Fees and Cuts, have called for a peaceful demonstration but warned that police were increasing the likelihood of confrontation with their promise of tough tactics.

"It is irresponsible for the police to use press conferences to ramp up the fear of violence -- which in any case has in the past come overwhelmingly from themselves -- thereby increasing the likelihood of it taking place," it said.

The students began marching last year over plans to triple university tuition fees, which were subsequently passed by parliament, but say their protest is now against a wider attempt to bring "market chaos" to the sector.

The move triggered a series of four demonstrations in London last year, culminating in a chaotic protest on December 9 when the car carrying Prince Charles and his wife Camilla was attacked.

Fears of violence have also been raised after London was rocked by riots and looting for four nights this summer.

Wednesday's demonstration will begin in the centre of London, travel south to Trafalgar Square and then head east with the route passing near to St Paul'sPo

The St Paul's demonstrators, inspired by the Occupy Wall Street movement in the United States, will be holding an event in solidarity with the students featuring political speakers and music groups.

Two other protests were also planned in London on Wednesday: taxi drivers will hold a "mass drive-in" at Trafalgar Square against licensing changes; and electricians will march on parliament to protest "de-skilling" of the sector.