Dame Vera Lynn has backed an urgent call to raise £1m (US$1.3m, €1.1m) before the end of the month in order to fund the purchase of “iconic land” on Dover’s white cliffs, amid fears the parcel could be picked up by property developers.

Overlooking the English Channel towards France, the White Cliffs act as a gateway to Britain and played an important part in the nation’s military history, with the cliff tops still home to installations and defences from the Second World War.

With a deadline of 22 September, the iconic heritage site is at risk should the National Trust – which currently manages the five mile range of chalk cliffs – not be able to purchase of the 700,000sq m (7.5m sq ft) land parcel.

Dame Vera, who this year turned 100 and in 1942 famously sung ‘The White Cliffs of Dover’, threw her weight behind the appeal, saying the cliffs represented British ideals.

“Those iconic white cliffs mean a great deal to so many people,” she said. “They were often the first sight of home for our brave boys as they returned from war, and they continue to represent important British ideals such as hope and resilience even in the most difficult times.

“It is vital that we do all that we can to preserve this important historical site, as well as the Cross Channel battery, for posterity, so that the memory of the past is never forgotten by future generations.”

If the National Trust is successful in its bid, the existing chalk grasslands will be restored, with the military structures made watertight. New access routes will also be created for visitors.

“There is something very special about the White Cliffs and for many people the site represents part of our cultural heritage,” said Virginia Portman, general manager of the White Cliffs of Dover.

“This unique coastal habitat is teeming with wildlife and being adjacent to land already in our care will provide better management options for the area.

“The site should be open for the whole nation to enjoy. It would be devastating if we lost the opportunity to protect it forever.

“A successful appeal will not only allow us to secure the land but also educate and inspire future generations.”

Donations to the appeal can be made here.