The needs of protected species are in danger of sending builders batty, according to law firm DLA Piper.

The likes of bats, great crested newts, otters and dormice now have even greater protection.

According to Rachael Histead, an associate in the firm's Birmingham office, two legal developments so far this year have made the hurdles for developers even more difficult to overcome.

She said: "There is no longer a clear distinction in the law between low level and high level disturbance.

"An operator or developer who believes that his operation or development could cause even low level disturbance must now consider whether he needs to obtain a protected species licence before carrying out the activities.

"It is no longer the case that the developer or operator can assume that low level disturbance does not require a licence. Licences will only be granted where strict legal tests are met. These require the applicant to demonstrate that there are 'overriding public interest' reasons for the operation/development to proceed and that there are 'no satisfactory alternatives'.

"Furthermore, the applicant must also meet the test that the 'favourable conservation status' of the species will not be prejudiced. This is the test that leads to expense being incurred by the developer/operator. In many cases it means that the animals need to be moved from their preferred location to newly created habitats, at the developer/operator's expense."

Secondly, guidance by Natural England in relation to planning permission issues effectively means that a developer cannot get on and prepare a site for development by moving protected species away from it under licence until all the details of the planning have been completed and signed off.

Ms Histead cautioned: "This is, in our view, an overly prescriptive and narrow approach which is not justified by the law and which is open to challenge.

"A further development is the form which now has to be filled out by the licence applicant which contains an enormous amount of detail as to the background and need for the project.

"Our advice is to seek legal support."