What price for White Cliffs of Dover?

What price could you get for the White Cliffs of Dover?

Woven into the national fabric as a symbol of wartime defiance, the cliffs stand immortalised by the voice of Vera Lynn and images of soaring Spitfires.

But how do we decide what is worth saving and what we would happily see destroyed to make way for development?

A National Trust campaign has just raised over £1m to buy a key stretch of the cliff tops to prevent any development.

Science editor David Shukman discusses whether some environmental treasures should be protected or if everything has a price.

The Editors features the BBC's on-air specialists asking questions which reveal deeper truths about their areas of expertise. Watch it on BBC1 on Monday 29 July at 23:10 BST or catch it later on the BBC iPlayer or on BBC World News.