Merseyside crime commissioner Jane Kennedy has joined seven of the UK's most senior police figures threatening the Government with legal action over the "potentially serious implications" of further police funding cuts.

Six police and crime commissioners have been joined by Stephen Greenhalgh, London's deputy mayor for policing and crime, in urging the Government to delay a decision on force budgets expected in this month's spending review.

In a letter to policing minister Mike Penning, the group said changes to the police funding formula would result in cuts that are "unfair, unjustified and deeply flawed".

Mr Greenhalgh has signed the letter alongside the police and crime commissioners of the Cumbria, Lancashire, Devon and Cornwall, Merseyside, North Yorkshire and Thames Valley forces.

The letter said: "The uncertainty and concern caused to the communities we serve by the review as it currently stands was entirely avoidable and wholly unacceptable.

"It is with much regret that we are therefore taking legal advice with a view to initiating a judicial review, should our concerns not be addressed."

Arguing that the Government had ignored its own consultation guidelines in drawing up reforms to the police funding formula, it said: "Regrettably, we feel the most recent consultation to be wholly inadequate.

"We have been given just three weeks to consider and comment on major revisions to the initial proposals. This is not in keeping with the Government's own guidelines on consultation, which were also ignored for the original consultation."

The letter highlighted the effects police cuts could have on its signatories' forces.

Chancellor George Osborne has asked ministers in non-protected departments - such as the Home Office - to come up with reductions in their budgets of between 25% and 40% by 2019/20 ahead of the Comprehensive Spending Review on November 25, when the Government's plans for the next four years will be set out.

Metropolitan Police commissioner Sir Bernard Hogan-Howe has previously said he is worried for the safety of London if the Chancellor announces cuts of £800m or more over the next four years, while Lancashire's chief constable Steve Finnigan warned that expected budget reductions of £60m will mean his force will "not be viable as we see it today" by 2020.

Police chiefs, including Sara Thornton, chair of the National Police Chiefs' Council, are giving evidence to the Commons Home Affairs Committee today.

The National Police Chiefs' Council said the letter was a matter for individual PCCs to comment on.