The de Havilland Aircraft Museum in London Colney has officially launched a £1million appeal to to build a new hangar to protect more of its unique collection of aircraft.

This follows the granting of planning permission earlier this year by Hertsmere Council, which will see the undercover display space at the Salisbury Hall centre nearly treble to replace the current small corrugated iron Robin Hangar, which is more than 80-years-old.

Alan Brackley, museum chairman said: "We have more than 20 aircraft and though we have two hangars, we still have to display some of them out in the open.

"It is so very important that we get them all under cover because some have wood and fabric in their construction so being exposed to the weather is not good for them. That is why our appeal is so very important in helping us preserve the de Havilland heritage."

De Havilland designed and produced aircraft at its Hatfield site from 1910 to the 1970s, including the famous "wooden wonder" Mosquito of the Second World War - the world’s first genuine multi-roll combat aircraft. Three examples, including the prototype, are the said to be the ‘museum’s jewel in the crown.’

Mr Brackley continued:"The museum also has the only surviving example of a DH106 Comet 1a fuselage still configured with the original window design. This was the world’s first licensed jet propelled passenger aircraft.

"Even our metal aircraft will corrode away if left out in the open, and this treasure must also be preserved as an example of man’s endeavor to push forward the frontiers of aviation technology."

The new hangar will abut the larger Walter Goldsmith hangar built some 30 years ago and is the next stage of the museum’s strategy to preserve, restore and display examples of the civil and military types designed by de Havilland at Hatfield.

It will have a mezzanine floor, enhanced de Havilland information and educational area, workshops for restoration work, and a refreshment area.

Mr Brackley added: "We believe that visitors will really appreciate our new hangar and we want to get it built as soon as possible, which is why our appeal is so very important."

"Our aircraft are of course the focal point of the museum, but it is important that we provide good facilities for all visitors, families, enthusiasts and school and youth groups."

The new hangar is the second stage of the museum’s development plan. Early last year a new Reception Foyer and Aeroshop were created.

As well as being Britain’s oldest aviation museum, founded in the 1950s, Salisbury Hall is the only museum in the world which has as many as three examples of the Mosquito, which was designed there when de Havilland moved its project from its Hatfield site to the hall, and where the initial prototypes were also built, and where later the Horsa troop-carrying glider was designed.

To find out more or volunteer to help run the museum as well as maintain and restore its aircraft visit: www.dehavillandmuseum.co.uk.