From former colonial splendours of the Raj to whaling stations in the South Atlantic, they are far-flung and fast crumbling outposts of Britain’s centuries-old overseas heritage.

The dilapidated and decaying legacies range from mansions and parks that were the pride of imperial India and Burma to churches, cemeteries and plantations fading away from neglect on tropical islands in the Andaman and Caribbean seas.

But a leading British conservation and heritage expert has now made the economic case for Government support to help save colonial and industrial treasures to promote Britain abroad as well as to bolster local regeneration.

“At a time when so much public debate is focussed on Britain’s role in Europe, I think we often forget that we built much of the modern world,” Philip Davies, a former director of English Heritage, told The Telegraph.

“Heritage-led regeneration works. It pays real economic dividends. Historic buildings and neighbourhoods are a huge economic and cultural asset.”