Two of the county’s biggest wildlife organisations have expressed “significant concerns” over the potential impact on birds and protected habitats from proposals that could increase flying at a former Suffolk airbase.

The RSPB and Suffolk Wildlife Trust (SWT) fear more flights at Bentwaters could increase disturbance to nesting birds, while the Suffolk Coast and Heaths AONB team also has strong concerns.

In a boost to campaigners, the organisations are calling for tight controls on the number of flights, restrictions on types of aircraft permitted, and no helicopters allowed as they cause the greatest disturbance to wildlife.

The AONB team and SWT have lodged formal objections to the new blueprint for Bentwaters – until their concerns can be adequately addressed.

Bentwaters Parks and Stansall Properties Ltd are seeking permission for 960 air movements a year – less than two flights a day – for a Spitfire, heritage aerobatic aircraft, some business flights, and an airshow.

The applicants say the aim is to regularise flying and not to greatly increase flights.

The RSPB though says while new documents show greater clarity regarding flights, and potential impacts on the Sandlings Special Protection Area, “some significant concerns remain”.

Conservation officer Jacqui Miller said: “We note that tenants at the site may change in future and that there can be no guarantee that the type of aircraft or their operators at the site would remain unchanged.

“We therefore recommend that the proposed planning condition should include a restriction on the type of aircraft, as well as the number of flights, and in particular that the site should not be used for the stationing of helicopters. This is because helicopters are recognised as likely to cause high levels of disturbance to birds.”

James Meyer, conservation planner for SWT, said the trust remained concerned about the control of the flying and the scale of any annual airshow.

He said: “It appears that appropriate mechanisms, such as planning conditions, could be used to provide tighter controls to help address the issues raised, however these are not currently present within the application.”

AONB manager Simon Amstutz said: “Our main concern is that of the potential disturbance to people and wildlife as a result of the application. Our concern is exacerbated by the proposed use of the site by aerobatic aircraft.

“In our view the only way to control the risk of increased disturbance is to control the number of flights and the type of aircraft using the site to a level which is deemed by the appropriate authorities to pose no risk to the purpose of the protected sites.”

Planning consultant Steven Bainbridge, of Evolution Town Planning, for Bentwaters Parks, said noise assessments submitted to Suffolk Coastal were based on worst case scenarios and not actual flying that would take place.

He said: “Military low flying in the area around Bentwaters is widely accepted as being far more frequent than the aviation activity proposed to be limited in this application. This is why the applicants firmly believe their proposals sit against an established background of wider aviation activity in the area and will have no significant adverse impact on tranquillity.”