The Government's controversial reform of the police funding formula is in "disarray", Labour has claimed, after a senior official acknowledged errors in the way forces' allocations had been calculated.
Shadow policing minister Jack Dromey said 31 of the 43 forces in England and Wales were set to lose out as a result of what he described as the "monumental incompetence" of the Home Office.
Policing Minister Mike Penning said the Home Office was still "refining" its proposed funding model and that forces' final allocations would not be settled until after the Government's spending review later this month.
The row erupted amid bitter controversy over the planned changes with six police and crime commissioners (PCCs) threatening the Home Office with legal action amid fears they are set to lose millions of pounds in Government support.
Mr Dromey released a letter from the Home Office director general for crime and policing, Mary Calam, to the office of the Devon and Cornwall PCC in which she admitted that some of the data used to calculate the allocations was out of date and had been updated.
"I would like to again confirm that it is this updated measure that we propose to use in determining final allocations," she said.
Mr Dromey said the disclosure would throw forces' financial planning into chaos, with three-out-of-four now facing further cutbacks.
"The Government have seemed intent on keeping the public and police forces in the dark about their unfair proposals, and now it emerges that they haven't even been providing forces with the right statistics," he said.
"This throws into disarray the figures given by the Home Office to police forces, and yet only one force of the 43 has even been told that the current figures are wrong."
The chief executive of Devon and Cornwall PCC Andrew White has now written to other forces saying the commissioner, Tony Hogg, was now "minded" to make representations to Home Secretary Theresa May to abandon the whole process and asking whether they would support him.
In a statement, Mr Penning said that the Government had been consulting on the principles for reform of the funding arrangements to ensure they were "fair, robust and transparent".
"We are refining our proposed model in light of responses to the public consultation and are engaging further with police and crime commissioners and forces as part of this process," he said.
"Allocations for individual police force areas have not been set and decisions on funding will not be made until after the spending review reports in November."