The island, which have only 4,000 people, can only be reached by water on Royal Mail ship St Helena. The ship needs to be replaced now by new one which will cost 64 million pounds.
So Britain plans to built the airport which will bring financial independence to St Helena. The previous Labour government dropped its plan for the airport due to soaring costs.
"Britain had an obligation to build the airport on St Helena, which will bring solution to St Helena's stagnation and perpetual dependence on UK aid." said Andrew Mitchell, International Development Secretary.
St Helena measures about 16 by 8 kilometres and has a population of 4,255 (2008 census).
The island was first discovered as an uninhabited island by the Portuguese in 1502. It is one of the most isolated islands in the world and was for several centuries of vital strategic importance to ships sailing to Europe from Asia and South Africa.
For several centuries, the British used the island as a place of exile, most notably for Napoleon Bonaparte, Dinuzulu kaCetshwayo and more than 5,000 Boer prisoners.