Cllr David Jeffels, portfolio holder for leisure and tourism at Scarborough Council, gave the keys to Lord Derwent, who is the chairman of the museums trust.

The grade II* listed building is now ready to reopen following a two-year makeover costing £4.4 million.

Cllr Jeffels, who is also one of the museum’s trustees, said: “I think the transformation of the Rotunda is fantastic. It’s going to be a real gem as far as the tourist industry’s concerned.

“This is going to make Scarborough a focus of the geology world – not just nationally but internationally as well.

“The exciting displays inside coupled with the splendid outdoor works on the Aquarium Top provide a fantastic gateway to Scarborough’s South Bay.”

Shirley Collier, chief executive of Scarborough Museums Trust, said: “The Rotunda may be a small building, but it is a big part of Britain’s scientific heritage. We’ve got innovative displays and activities which will appeal to all ages, especially children who are mad on dinosaurs.”

Following the reopening ceremony tomorrow, the building will open to the public on Saturday.