A �100,000 project shows just how far a group of environmental scientists will go to protect the habitat of Britain’s only venomous snake – and help Norfolk buck an alarming national decline in adder numbers.

While major construction projects can, too often, be harmful to wildlife, their efforts have ensured the �120m-plus flood alleviation project being carried out across Broadland has had a beneficial effect on reptiles.

Ecologists working for Broadland Environmental Services Limited (BESL) – the consortium behind the 20-year flood defence programme – are ensuring the Broads are still home sweet home to the adder.

A 300m-long adder bank built at Horsey has provided a safe haven from the earth-moving diggers fashioning new flood defences nearby.

Senior environmental scientist Christian Whiting said: “It is probably the biggest adder bank built in the UK today and has been specially designed with reed bundles and tree branches inside to provide places to burrow.”

More than 170 adders had to be relocated ahead of the work at Horsey and about 100 were rehomed on the bank, the south-facing slope of which provides the perfect place to enjoy the spring sunshine.

He and his team, using strong gloves to catch the snakes, have been marking each one with dye and recording them on a comprehensive database.

Since they began their adder surveys in 2008 they had confirmed healthy populations in other locations such as Fritton and Belton as well – and, ahead of flood defence work at Hickling, they would be doing a similar study there.

Ecologist Phil Parker, of King’s Lynn, recorder for the Norfolk Amphibian and Reptile Group, agreed with Mr Whiting’s assessment that Norfolk was still a stronghold of the adder.”

He said Mr Whiting’s work had shown surprisingly large adder numbers in Broadland sites, such as Fritton’s Waveney Forest, which were not the typical heath or grassland habitat.

Mr Parker said the public could play an important role in mapping the adder across the county.

“We have lists of sites where they have been seen in the past. It would be great if people could help to look for them.

“Knowing their location is vital because simply pulling down a tree might destroy an entire hibernating colony if no one knew they were there,” he said.

Volunteers are invited to email philipparkerassociates@btconnect.com