Experts have begun the delicate task of cleaning barnacles and silt from a rare German Second World War Dornier 17 bomber which has been at the bottom of the sea for more than 70 years.

Conservation staff at the RAF Museum in Cosford, Shropshire, are using a very dilute acid to clean away the debris that has stuck to the aircraft.

The remains of the largely intact bomber were lifted from the bottom of the English Channel where it has lain since being shot down in the Battle of Britain.

In what is believed to be one of the largest recoveries of its kind in British waters, the aircraft was brought ashore and transported to the museum more than 200 miles away.

The Dornier, including the main fuselage, the wings and both propellers, is now inside two specially built polytunnels, being treated with a special cleaning solution.

Darren Priday, deputy manager of conservation at the museum, explained the process of getting the aircraft ready for full public display could take at least 18 months.

"There's no example of a Dornier 17 as complete as this one anywhere," he said.

"Now the parts are in the polytunnel, they are being sprayed with an irrigation system.

"It's citric acid, pH-balanced in water, and the idea is that will remove the impurities from the salt water and also the crustaceans that are on the air frame at the moment."

The public can see exactly how the conservation work is progressing as the exhibit is open to visitors.

The bomber, 1500 of which were built, was discovered by divers in 2008.

Sonar scans by the RAF Museum, Wessex Archaeology and the Port of London Authority confirmed the identity of the aircraft.

Mr Priday said it would be moved to the RAF Museum in London after cleaning.