Twelve people have been arrested after clashes with police marred student protests in central London.

The Metropolitan Police said smoke bombs and eggs were thrown at officers by a handful of demonstrators during the rally, organised to call for free education.

In a statement, Scotland Yard said a "small group of protesters" had thrown paint outside the Home Office and "another group attempted to push their way into the Department for Business, Innovation and Skills building but were prevented by police".

The march was organised to challenge plans to scrap maintenance grants and replace them with loans, which critics warn will plunge the poorest students into thousands of pounds of extra debt.

At present, full-time UK students from families with annual household incomes of £25,000 or less qualify for maintenance grants of £3,387 a year, with smaller amounts awarded according to income.

But under the changes, which come into force in the next academic year, these grants will be replaced by loans which students would start paying back when they earn more than £21,000 a year.

Deborah Hermanns, from the National Campaign Against Fees and Cuts, said: "We know that the fight for free education doesn't end at the end of this demonstration.

"We are not just marching for one day and for the abolition of fees. We are building a movement which can strike to win, just as other movements all over the world have won."

The trouble flared when the protest came to a stop outside the Department for Business, Innovation and Skills (BIS).

Dozens of officers from the Metropolitan Police Territorial Support Group moved in and clashed with some demonstrators clad in black and with scarves covering their faces.

Some let off flares and one was thrown towards police.

The protesters burst through the police lines and ran down Victoria Street, cheering and waving flags.

Dozens of police officers gave chase as the marchers darted through central London traffic.

Elsewhere, one female protester lay in the street, clutching in her head in pain, as demonstrators were kettled near St James'.

Dozens of uniformed officers pushed demonstrators back as they said they were going to provide the stricken woman with medical attention.

Earlier, shadow chancellor John McDonnell accused the Government of "betraying" students as he addressed the crowd.

Labour leader Jeremy Corbyn also threw his support behind the protesters by demanding the abolition of tuition fees in a statement read out at the rally.

A BIS spokesman said: "This Government is committed to ensuring everyone with the potential to benefit from higher education has the opportunity to do so, regardless of their background.

"It has always been the case that student support provided by government is a contribution to living costs, and institutions themselves offer a range of bursaries, scholarships and grants.

"Our system means that lack of finance should not be a barrier to participation and more funding is available to support living costs than ever before."

A further day of action has been called on November 17, focused on the treatment of international students, migrants and refugees.