Britain has suffered another defeat in its fight to hold onto a cluster of islands in the Indian Ocean.

A meeting of the world’s postal unions in Cote D’Ivoire has voted, overwhelmingly, to block the use of British stamps from the Chagos Islands.

All post to and from the remote archipelago must now have stamps from Mauritius – the country which claims control of Chagos.

A set of pretty postal stamps showing sea slugs and angel fish might not seem like the sharp end of international diplomacy.

But the near unanimous vote to make those stamps illegal, worldwide, is a blow to Britain, and another sign of its growing isolation over its claim to the Chagos Islands.

Three powerful UN bodies have already ruled that the archipelago is part of Britain’s old colonial empire and should be handed to Mauritius immediately.

Britain insists it will only do so when the islands are no longer needed for security purposes – America currently uses one for a military air base.

The immediate impact of the international postal union vote is that stamps marked British Indian Ocean Territory won’t be recognised.

Hardly devastating.

But the next step could see Mauritius seeking to ban international flights over the area – a vast chunk of the Indian Ocean.

All indications so far show that Britain has almost no allies left on the Chagos issue.