THE discovery of a rare bumblebee at a water treatment works has given new hope to those studying Britain's under-threat bee population.

Thames Water has announced that several colonies belonging to Moss Carder Bumblebees have been found at their site in Coppermill Lane, Walthamstow.

Bee numbers have been sharply declining in recent decades, prompting international concern as an estimated one-third of the human diet relies on food produced via insect pollination.

Disease, poisoning from pesticides and a reduction in suitable habitats have all been identified as possible reasons.

It is thought the species has been attracted by the relative tranquillity of the sprawling site – which treats and pumps 560 million litres of water to homes across east London and Essex every day.

The colonies are underground in grassy areas of the complex and are only visible from small holes in the earth - about the size of a five pence piece – which the bees use as an entrance.

Cathy Purse, Thames Water's biodiversity engagement manager, described it as “an exciting discovery”.

She said: “We’re really lucky at Thames Water that we have these green spaces which attract so much wildlife.

“Often they're not accessible to the public so bees can buzz around the wild plants and flowers without being disturbed.

“When bumblebees as rare as these are discovered it's great news and because of secluded nature of the Thames Water sites they have a great chance of thriving."

It comes as the even rarer Shrill Carder Bumblebee, which is thought to be extinct in many parts of London, has also been discovered at a Thames Water works in Bexley.

Gill Perkins, conservation manager for the Bumblebee Conservation Trust, said: “Finding such threatened bumblebees at the two Thames Water sites is great news, and it shows how important it is to forge partnerships between landowners and conservation charities and the need to carry out detailed surveys of key species.

“In the last 70 years two bumblebee species have become extinct and many more have declined rapidly.

“It’s easy to take them for granted, but without their work as pollinators, our crops would be less productive and our wildflowers would produce fewer seeds. We need our bumblebees”.