Police chiefs have defended their screening policy after it emerged that a third of crimes reported in Norfolk are not investigated by officers.

Police chiefs have defended their screening policy after it emerged that a third of crimes reported in Norfolk are not investigated by officers.

Figures released by Norfolk Constabulary show thousands of crime reports get no further than civilian call-handlers, under the supervision of an officer, who are trained to decide whether or not an incident is serious or solvable enough to warrant further investigation.

Opponents of the policy claimed the figures proved the force was under-resourced and under too much pressure to chase government targets.

However, senior officers defended the system, saying it helped it to make the most of limited resources, and that no category of crime was risk-free for the culprits.

During 2006-07, 20,739 crimes were screened out from a total of 62,626 reported - a rate of 33pc, which is just below the national average of 39pc.

Of those, 9,375 thefts and 8,819 cases of criminal damage were not investigated. Other crimes not probed included burglaries, violent crimes and drug offences.

Det Supt Julian Gregory, of Norfolk police, said: "As with any public sector body we have a budget and finite resources and it is vitally important to target those resources to where we get the best benefit for the community. It is common sense.

"We only screen out if there's nothing to indicate that we are going to get anywhere with it. If a crime is screened out, it's screened out for the right reason.

"But crimes are always worth reporting and we look at crimes in all different ways, on an individual basis and if it links with a broader problem."

Det Supt Gregory said the most serious "mandatory" category of crimes would always be screened in, but for less serious "non-priority" incidents, telephone staff would ascertain the solvability of the crime based on likely lines of inquiry, identified suspects, or identifiable property.

He said crimes screened out through this process would still be passed to safer neighbourhood teams if community reassurance was needed.

Norwich North MP Ian Gibson said 33pc seemed to be a very high number and called for an explanation.

"The police force needs to explain in more detail about why these crimes are not being investigated, because I think members of the public really need to know," he said.

Norman Brennan, chairman of the Victims of Crime Trust and a serving police officer, said: "The sad reality is that police numbers have not kept pace with the huge rise in crime across the spectrum.

"The public are our masters and have a right to know

why we don't turn up to every call and investigate every crime."

Screened out offences are still counted in official crime figures, and victims are issued with reference numbers for insurance purposes.

Norfolk was one of 12 English and Scottish forces which released the figures under Freedom of Information laws. Suffolk Constabulary does not operate a screening policy.