Angry police officers in the West Midlands have booked 39 coaches to take them to a demonstration over pay in London next week.
The huge turnout for the protest demonstrates the level of anger with the Government, after Ministers refused to meet a 2.5 per cent pay increase in full, the Police Federation claimed.
Paul Tonks, chairman of the federation's West Midlands branch, said: "This is a huge turnout and it should leave Ministers in no doubt about the strength of feeling."
The coaches will ferry officers working for West Midlands Police to a national demonstration in Westminster, central London, next Wednesday.
Police from across the country are to protest and lobby their MPs, after the Government delayed over the 2.5 per cent pay award.
The deferment means the annual pay increase is effectively 1.9 per cent, which police say is less than the amount recommended by an independent panel. The dispute has become so bitter that police are planning to hold a ballot on whether or not to demand the right to take industrial action.
In the run-up to the protest, the Police Federation has produced a poster describing Jacqui Smith, the Home Secretary and Redditch MP, as "Jacq the Rip Off", a reference to the Victorian serial killer Jack the Ripper.
But Ms Smith has also come under increasing pressure from her own backbenchers, with more than 100 Labour MPs calling on her to back down.
A House of Commons motion calling the dispute "petty and needless" and urging the Government to "reconsider" has been signed by MPs including Jim Cunningham (Lab Coventry South); Brian Jenkins (Lab Tamworth); John Spellar (Lab Warley); Lynne Jones (Lab Birmingham Selly Oak); Janet Dean (Lab Burton); Paul Farrelly (Lab Newcastle under Lyme); Richard Burden (Lab Birmingham Northfield); Charlotte Atkins (Lab Staffordshire Moor-lands); Khalid Mahmood (Lab Birmingham Perry Barr), as well as former Labour MP Clare Short (Ind Birmingham Ladywood).
Roger Godsiff (Lab Birmingham Spark-brook & Small Heath) called on the Home Office "to overturn her current policy and honour the agreement reached by the arbitration panel".
A number of Conservative and Liberal Democrat MPs have also expressed support for officers.
Mr Tonks said: "If the Government thinks this issue is disappearing, it is set for a shock. There are a lot of battered and bruised bobbies out there.
"This is not just about pay, it is also about the process of agreeing pay. It is about the Government's lack of integrity in reneging on an agreement.
"Every officer taking part in the demonstration is taking a day off or is on holiday. Nobody is coming down while on duty."
Jan Berry, national chairman of the Police Federation, is to meet Ms Smith tomorrow for last-minute talks which could avert the march if an agreement is reached.
If the event takes place as planned, it is expected to be attended by 20,000 officers, making it the largest police demonstration since 1919.
The Government's determination to keep the pay increase below two per cent is part of a high-profile effort by Gordon Brown, the Prime Minister, to keep public sector pay under control. He argued that this was essential in order to avoid inflation.
The prominence given to the issue by the PM means it is unlikely the Government could back down without a loss of face.
West Midlands Police Authority, the body responsible for funding the region's force, said it has the money to pay the 2.5 increase in full. It said it was "extremely disappointed" in Ms Smith for blocking the pay increase and has joined calls for her to change her mind.