West Mercia Police could get a four-month stay of execution if it refuses to merge with neighbouring forces,
But Charles Clarke, the Home Secretary, indicated his preference was for a regional force, and insisted police chiefs could not block reforms.
He said: "We want to reflect regional boundaries if that is possible. That is the consultation now taking place."
The Home Secretary was speaking to the annual lunch of the Newspaper Conference, whose members include The Birmingham Post.
Police forces including West Mercia, Staffordshire and Warwickshire have been told they need to merge because they are currently too small to cope with the threat of terrorism and organised crime.
Options include merging all three with West Midlands to create a giant regional body.
But the proposal has been fiercely opposed by West Mercia, which was recently named the most efficient in the country by independent inspectors and wished to remain independent.
In an informal meeting in the House of Commons, West Mercia Chief Constable Paul West told Home Office Minister Fiona Mactaggart the Government was pursuing the "wrong model".
Mr Clarke said yesterday: "If there is a consensus in a particular area, for example the West Midlands, about the change that ought to happen, then I have the right to say, off you go.
"If there is controversy and no agreement, I then have to decide what to do. I have the power to say, I want you to look at this, and then there would be a four-month consultation."
Mr Clarke said the reforms would not create distant police services. They would be accompanied by greater moves towards neighbourhood policing.
The Home Office privately insists that there is no possibility of West Mercia continuing in its current form.
Last night West Mercia Police Authority revealed 88 per cent of people who have contacted it to express views want the West Mercia force to continue as an independent constabulary.
The authority wants the force to be enhanced so it has the resources to deal with terror and organised crime.
Conservative MPs have continued their opposition to the Home Office proposals.
Speaking in the Commons, Owen Paterson (Con North Shropshire) said: "We are being forced into an enormous West Midlands force. There is no operational necessity to force us in with a monster force."