The Government must improve upcoming planning systems or risk giving developers 'carte blanche' to concrete over green spaces, MPs have warned.

Proposals outlined in a Green Paper consultation would allow developers to offset the environmental impact of their projects by restoring or recreating additional natural habitats.

However the Environmental Audit Commission has warned calculations used to work out biodiversity losses at a site remain overly simplistic, amounting to little more than ‘a 20 minute box-ticking exercise’.

Planning proposals outlining plans for biodiversity offsetting must ‘rigorously’ protect ancient woodland, MPs said.

Methods to determine the impact of a development on a habitat must take into account the significance of rural spaces, ecosystem services such as flood prevention, and the local connectivity of habitats - according to the commission.

Biodiversity offsetting should be a mandatory requirement in the planning system, the cross party panel of ministers said, but systems would be needed to ensure developers did not merely replicate low-cost habitats.

Chair of the committee, Joan Wallen, said: ‘Biodiversity offsetting could improve the way our planning system accounts for the damage developments do to wildlife, if it is done well.

‘Many witnesses to the inquiry were concerned that the Government's proposal would allow offsetting to be applied to ancient woodland and Sites of Special Scientific Interest. There is a danger that an overly simplistic offsetting system would not protect these long-established eco-systems.’

‘The assessment process currently proposed by the Government appears to be little more than a 20 minute box-ticking exercise that is simply not adequate to assess a site’s year-round biodiversity.

‘If a 20 minute assessment was carried out in a British wood in winter, for instance, it would be easy to overlook many of the migratory birds that may use it as habitat in summer.’