LANCASHIRE police bosses are threatening to pull the plug on a merger with the Cumbria force if demands over council tax are not met.

Lancashire Constabulary is to be merged with Cumbria police as part of a national move to create bigger forces to tackle terrorism and serious crime more effectively.

The two forces are the only ones in the country to merge voluntarily and it is set to go through by April next year but a new governing police authority must be in place by next month.

And when the new force is launched a new council tax level for police services will be set.

However the merger is facing possible collapse as the county force's governing body, Lancashire Police Authority, wants cast iron guarantees over the way council tax for police services will be set.

Now members have warned that unless the Home Office provides these assurances: "The deal's off".

As revealed earlier this year, Lancashire tax payers' bills for police services could rise by 13 per cent, while residents in Cumbria will be charged 22 per cent less than now.

Ministers have insisted that the levelling out of two forces' council tax is the only fair way to ensure residents do not pay different amounts for the same police.

The new charges have been calculated by dividing the total council tax collected in both Lancashire and Cumbria by the number of tax payers.

But Lancashire Police Authority insists it only voted to go ahead with the merger on the condition the changes would be phased in over a period of up to three years.

But the Home Office has so far failed to agree on this and as the merger stands, it is favouring bringing all tax levels in line over a maximum five year period, while the Home Secretary would control the timetable of the tax changes and could cap the tax rises.

But Lancashire Police Authority, in agreement with Cumbria, has again contacted the Home Office demanding the merger conditions are revised so it allows "harmonisation in three equal steps".

These would see an increase of £4.55 each year for a Band D taxpayer in Lancashire (currently £113.09) and a reduction of £12.10 each year in Cumbria.

Chairman Coun Malcolm Doherty warned at a full meeting of the authority: "We are standing firm on this.

"We still want the merger to work but will agree to it only if the right conditions are in place."

Members agreed, and Acting Chief Constable Steve Finnigan remained upbeat although issues needed to be ironed out.

He said: "The feeling remains that this merger is the right thing to do."