Fifteen smaller police forces could be scrapped in the biggest reform of policing in England and Wales for more than 30 years.
Recommending the overhaul, Her Majesty's Inspectorate of Constabulary (HMIC) warned that the way policing was organised was unfit for the 21st century. It sounded the death knell for smaller rural forces by concluding that those with more than 4,000 officers tended to perform more efficiently.
Charles Clarke, the Home Secretary, is to accept the report and approve the creation of several new "super-forces".
The current structure of 43 forces, dating back to 1974, could be replaced by fewer than 30.
Although the Home Office stressed that no final decisions had been made, several forces are doomed. Norfolk (1,554 officers), Suffolk (1,323) and Cambridgeshire (1,418) face amalgamation into an East Anglian constabulary. Mr Clarke, a Norfolk MP, has already described that move as "perfectly rational".
The smallest county police force, Warwickshire (1,012), looks certain to be merged with a larger neighbour, probably the West Midlands.
Wiltshire (1,228) and Dorset (1,475) seem untenable and could be amalgamated with their larger neighbour Hampshire.
Three of the four Welsh forces - Dyfed-Powys (1,183), Gwent (1,438) and North Wales (1,676) - have fewer than 2,000 officers.
Other forces with fewer than 2,000 are Bedfordshire, Cleveland, Cumbria, Durham, Gloucestershire, Lincolnshire, Northamptonshire, North Yorkshire and Surrey.
The City of London Police (881) may survive because of the unique challenges in protecting the Square Mile.
The HMIC report concludes: "Put simply, the 43-force structure is no longer fit for purpose. In the interest of the efficiency and effectiveness of policing, it should change.
"Our conclusion is that below a certain size there simply is not a sufficient critical mass to provide the necessary sustainable level of protective services that the 21st century increasingly demands."