Concreting over your front garden could be killing off the local bird population.

That is the warning from the RSPB to Kent householders as the bird population plummets while the number of patios in the south east rises.

Around a fifth of front gardens in the region are now mostly concrete, which the charity fears may limit the availability of insects for birds to feed their young with.

Numbers of song thrushes, house sparrows and starlings have all plummeted in Kent over the last 30 years, particularly in urban areas, where paving over front gardens to provide extra parking is becoming increasingly common.

The RSPB is now welcoming tough new legislation, which comes into law on Wednesday, that requires anyone wishing to lay concrete over their front gardens to get planning permission, although this will not be required for surfaces that allow water to seep through and plants to grow.

Hester Phillips, of RSPB South East, said: "We welcome the new measure because it will protect land that supports our fragile urban wildlife, and will also help address flash flooding, which can devastate rivers and streams and the wildlife they support."

She added: "This legislation is a win-win situation for everyone. Homeowners still get to create a parking bay, but by using permeable surfaces they’ll also help support a range of plants, insects and birds, while protecting their homes and the environment against floods."

RSPB research shows that even tiny front gardens or green verges are vital for urban wildlife, housing up to 786 different species of insect.