Court bid to keep Rock British

Gibraltar residents are preparing to go to court in a last-ditch bid to stop the British Government from selling out to Spain.

They fear that Tony Blair will ignore public opinion and strike a joint sovereignty deal with the Spanish this summer.

The Rock's chief minister, Peter Caruana, said that he was taking legal advice on how the colony's 1969 constitution could be used to block such a move. "We are seeking courts in which we can get a judicial adjudication. We are investigating all options," he said.

Mr Caruana was speaking in London ahead of today's launch of a political campaign to rally the British public against Labour's proposal.

A lengthy court case would be hugely embarrassing for the Government which is already under attack on the issue from backbench Labour MPs as well as the Conservatives. Last month 25,000 of Gibraltar's 30,000 residents marched for the right to stay British.

The tiny colony, at the southern tip of the Spanish mainland, was ceded to London by Madrid "in perpetuity" under the 1713 Treaty of Utrecht. The Spanish government has seized on a section of the treaty claiming that local residents should not have a veto over the Rock's status. Foreign Secretary-Jack Straw and his Spanish counterpart Josep Pique are close to agreeing a deal under which the two countries would agree on a system of joint sovereignty.

Any deal will be put to the people of Gibraltar in a referendum, most likely in the autumn. It would almost certainly be rejected but, crucially, it would remain on the table as the preferred option of both governments.

Mr Caruana said: "It would hang over us like a Sword of Damocles. We want to remain British to a man, woman and child."

His case is likely to highlight the preamble to the 1969 constitution that the Government "will never enter into arrangements under which the people of Gibraltar would pass under the sovereignty of another state against their freely and democratically expressed wishes".

A joint sovereignty agreement could end centuries of bitterness between Spain and Britain. Madrid would lift border restrictions and the European Union would seal the transition with a £37million grant to boost the economy. Gibraltarians, however, dismiss the payoff as a bribe.