Police helicopters may be unable to reach Suffolk within key target times after the county’s current base is closed, according to new data produced in opposition to the proposals.

The National Police Air Service (NPAS) announced last week that it was planning to close 10 bases across the country by 2017, including Wattisham, as part of cost saving measures.

NPAS pledged to deliver an “effective and efficient” service and claims all the country will be accessible within 30 minutes from one of its 15 remaining bases.

But a map, allegedly produced by helicopter pilots opposed to the changes, gives its own coverage estimation, factoring in preparation time, which leaves vast swathes of England, including much of Suffolk, outside a 25-minute radius.

Suffolk’s Police and Crime Commissioner Tim Passmore already expressed concerns about the value for money provided by the service, when it emerged the county’s force paid £800,000 for helicopter use in 2014 but received only half its allocated flying hours.

He reacted to news of Wattisham’s closure and the forecasted coverage offered by Suffolk’s nearest remaining base in Boreham, Essex, with more disappointment.

“On face value it looks like there are some pretty serious implications for Suffolk,” he added. “There’s no way I’m prepared to put up with a second-rate service from NPAS or anyone else.”

Mr Passmore said he would be calling for answers to key aspects of the closure, including how long the helicopter could patrol above Suffolk on a tank of fuel and whether the county would be expected to pay for “dead flying time” as it travelled up from Essex.

“The bottom line is we have to get a proper deal for Suffolk,” he added.

“We need urgent clarification from NPAS about flight times, costs and how this proposal will affect Suffolk. At the moment their communication has been dire.”

NPAS said it stood by its original maps.

It added the principle of “borderless tasking” meant aircraft could be deployed from places other than air bases.