The Marine Resources Assessment Group has a agreement with the government to manage fishing in the area. It says there is no proof a reserve would improve the environment.

MRAG development director Chris Mees said: 'Shark finning is banned entirely, unlike elsewhere in the Indian Ocean. If you close the fishery, those boats will be displaced to areas where there is fewer control.'

The Chagos Islands - or the British Indian Ocean Territory - comprise the world's biggest coral atoll and have one of the healthiest reef systems on earth. They are home to 220 coral species and 60 species scheduled as 'endangered' on the ICUN Red List.

Foreign secretary David Miliband announced in November that there would be a discussion about a fishing ban around the Chagos. A conclusion is expected this spring. The foreign office at present earns between £700,000 and £1million a year from selling fishing rights in the area.