The museum asked for the one-off payment

Tony Blair announced a �500,000 Department for Culture, Media and Sport grant at a party to celebrate the museum's 250th anniversary.

And the British Council in Africa will provide office and staffing resources to help with the proposals.

The museum asked for the one-off payment instead of lobbying for an increase in its annual grant.

It now said it will pursue this policy far more in the future.

Other museums and galleries that complain of underfunding are likely to follow suit.

Jobs lost

Despite receiving nearly �40m of government money every year, the museum - home to the Elgin Marbles and the Rosetta Stone - says funding has declined by a third in real terms during the past decade.

Jobs have been lost and galleries closed to the public.

In his first speech on the subject of museums since coming to power, the prime minister said the museum, with five million annual visitors, was a "fantastic, national resource".

And the project would coincide with Britain's presidency of the G8 group of nations, focusing on the plight of Africa.