Police last night accused the government of attempting to ban 10,000 officers from marching through Westminster in a mass protest over their pay award. The demonstration would be the force's biggest since 1919.

Relations between the Home Office and the force have fallen to a new low, with the Police Federation of England and Wales, the body that represents 124,000 rank-and-file officers, claiming the government is 'interfering behind the scenes' over plans for the march to Parliament on 23 January.

The high-profile demonstration, intended to highlight the force's anger over its recent below-inflation, 1.9 per cent pay rise, is threatening to become a major political flashpoint in the new year. The police claim their preferred route for their march is set to be banned under archaic 'sessional orders', laws drawn up in the early 19th century to combat large-scale radical protests that threatened a disturbance of the peace.

The orders are renewed by Parliament each year and invoked by the Metropolitan Police if the force believes a protest will prevent MPs from going about their daily business. Critics of the orders claim they are a heavy-handed response designed to stifle peaceful protest.

Last night the federation claimed that parliamentary officials were in talks with the Met with a view to banning the march outside Parliament and said the government had no intention of lifting the orders so that the protest could go ahead. 'There appears to be some behind-the-scenes government interference,' said Alan Gordon, vice-chairman of the federation. 'There is pressure being brought on the Metropolitan Police to either postpone the march altogether or to reroute it in such a way that it will disappear into side streets where it will be out of the public gaze.'

The latest skirmish between the thin blue line and the government follows months of bitter wrangling over pay. Earlier this year there was widespread outrage among police officers in England and Wales after they discovered that a 2.5 per cent pay rise was not going to be backdated. It meant their real pay rise was 1.9 per cent.

Rank-and-file officers will shortly be balloted on whether they should have the right to take industrial action, which is currently illegal. Any move to ban or reroute the march would heighten tensions between the two sides in the run-up to the ballot.

'The government is extremely embarrassed by this whole affair,' Gordon said. 'They realise they have made a crass decision by not backdating this pay and I think they were hoping that the whole problem would disappear over the Christmas break.'

The government denied it was attempting to block the protest. A Home Office spokesman said any decision on the march was not up to the government. 'The decision is a matter for the Metropolitan Police,' the spokesman said.

The Met confirmed it was in talks with the federation over whether the march would go ahead. 'We are in discussions with the Police Federation regarding the planned demonstration on 23 January,' a Met spokeswoman said.

Gordon said using archaic orders to ban or reroute the march on law-and-order grounds would widen the rift between the police and government. 'To think there is a likelihood of public disorder from 10,000 police officers marching through central London is a nonsense,' he said. 'I can only assume they are doing this because they do not want the embarrassment. It will just raise the police's anger and mistrust of this government.'