Four police forces in the West Midlands region are set to be the first to merge in a reorganisation plan. Warwickshire, West Midlands and Staffordshire forces want to merge with each other. But a fourth force, West Mercia, wants to be left alone.
Home Secretary Charles Clarke announced the proposals for one service for the whole region on Monday.
He believed there was "only one acceptable option" for each of the four regions affected by his annoucement.
Mr Clarke also made proposals for Wales and some northern English regions.
He wants to see the existing 43 forces in England and Wales cut back, creating larger regional forces.
The Home Office has said forces should have at least 4,000 officers. Warwickshire, West Mercia and Staffordshire forces fall well below the figure in their current form.
Mr Clarke has said larger "strategic" forces will help police combat terrorism and organised crime, and also enhance neighbourhood policing.
Across England and Wales, some 13 forces had expressed a desire to merge, 14 wanted to "stand alone", and the remaining 16 had no preference or were undecided.