The West Yorkshire chief constable told an influential committee of MPs that the merger of police forces in England and Wales to create larger forces is "inevitable".

He believes that just one high profile mistake or error could trigger renewed calls to resurrect the idea of larger strategic police forces.

Sir Norman, head of future developments at the Association of Chief Police Officers, said: "It is events that will bring this back to the agenda.

"It will be the failing of a force to do what is required in the 21st century that will cause people to ask whether (a force] is suitably equipped, whether it has got capacity capability to meet the demands."

Merger plans were put forward in 2005 by former Home Secretary Charles Clarke, who aimed to reduce the number of forces in England and Wales from 43 to around 24.

The main driver behind the controversial plans was to create forces that were better able to tackle the threats of terrorism and organised crime.

Yorkshire's four forces were told they would have to merge to form a superforce.

But only North Yorkshire chief constable Della Cannings conditionally supported the move.

The plans were largely unpopular across the rest of the country.

Mr Clarke's successor John Reid axed the proposals after only Lancashire and Cumbria agreed to a voluntary merger and other forces faced being forced to amalgamate.

But Mr Bettison told the Home Affairs Select Committee it is becoming "more and more untenable" for each of the forces "to be technologically equipped and ready to support a police service in the 21st century.

"Whilst understanding the political realities of the previous policy proposals and disappearance of those from the table, it remains the professional view that a smaller number of strategically sized forces would be the best way of arranging ourselves against 21st century ills," he added.

He said the "tight fiscal environment" makes it difficult for forces to currently collaborate effectively. Smaller forces also fear their resources will get "sucked" into the urban areas if they work more closely with their larger neighbours.