Britain and Spain hope they have hit on a formula that will eventually solve a problem that has soured their relations for more than two centuries: the future of the Rock of Gibraltar.
The British Foreign Secretary, Lord Carrington, and his Spanish counterpart, Marcelino Oreja, have agreed to restore direct communications between the Rock and the Spanish mainland for the first time in 11 years.
But it is by no means certain that the 2.5 square miles of granite and 20,000 people who constitute Gibraltar are about to cease to be a problem.
The particular problem at Gibraltar is that its people regard themselves as distinct from Spain and, almost to a man, have no wish to see the Union Jack run down from flagpoles throughout their tiny teritory. If anything, Spain's blockade of Gibraltar since 1969 hardened the resentment of the locals against their much larger neighbor. They appear to believe that Gibraltar's future as a naval base and as a spot for sun-hungry Britons to flee, promises enough economic security.
That is not the way Britain sees the problem -- and it is certainly not the view from Madrid. Lord Carrington, like many another British foreign secretary, is under pressure from the United Nations to achieve the "decolonization" of Gibraltar.
Spain, which made the grave error of ceding the Rock to Britain under the Treaty of utrecht of 1713, still contrives to see Gibraltar as part of its realm. It regards Gibraltarians as Spanish subjects and can see no logical reason why this miniscule outcrop on the Iberian Peninsula should not return to the sovereignty of Madrid.
But there are at least two obstacles to such a course. In the first place, Spain is about to begin negotiating entry to the European community (EC). Brussels does not like high-handled behavior by states on questions of sovereignty that, to say the least, are blurred by legal argument.
It was because the EC is against frontier blockades in general that Madrid felt obliged to end the arrangements under which people wishing to visit Spain had to proceed via Tangiers in Morocco.
Even more awkward from the Spanish standpoint is the state of mind of the Gibraltarians. Many times they have been asked to vote on the question of integration with Spain, and just as frequently it has emerged that only a handful of inhabitants are prepared even to consider it.
Gibraltarians sense of being British presents difficulties for Britain, too. No doubt Lord Carrington would like to be rid of the problem of the Rock, but he cannot ignore the express wishes of Gibraltarians.
But there is a school of thought that believes the people of the Rock should not worrty too much for the present -- and that is not only because the wheels of diplomacy tend to turn slowly at the best of times.
Spain itself retains territories that present the government in Madrid with problems. King Hassan of Morococo has warned the Spanish authorities that if Gibraltar is ceded back to Spain, he will ask the enclaves of CEuta and Melilla in North Africa to be handed over to Morocco.
Economic advantage as well as national pride continue to cause the Spanish to hang on to their imperial remnants -- indeed, they are almost certainly as keen to keep them as Britain is to be rid of theirs.
The word in London and Madrid is that Gibraltar is likely to remain a problem that governments in both capitals are in danger of stubbing their toes on. The British flag will flutter at the craggy entrance to the Mediterranean for some time yet.