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Spain is suffering its worst drought in more than four decades, pitting the country's regions against each other in a fierce battle over water resources.

There has been 40 per cent less rain than usual since October 1 across the nation as a whole, according to the Meteorology Institute, although in some regions the impact has been far worse. Mediterranean regions such as Catalonia and Valencia have been the worst affected — they have had less rain than at any time since 1912.

Farmers in Catalonia fear they could lose their crops altogether if it does not rain in coming weeks, and Britons with homes on the coast could soon face restrictions on water.

The situation in Barcelona — Catalonia's capital and top tourist draw — could soon become critical. Water reserves there are at 19 per cent of capacity — they must be shut down when they reach 15 per cent because there is too much sediment near the bottom. José Montilla, president of Catalonia, said: “We must prepare for the worst.”

Meanwhile, other regions along the “green” northern edge of Spain, such as the Basque Country, have recently had to release water from their reservoirs as rivers threatened to burst their banks.

Most of the other regions along Spain's northern coast have had ample rain this year and have full reservoirs going into the summer.

Catalonia has tried to salvage matters by proposing to divert water from the River Segre to Barcelona. But Aragón, with which it shares the tributary, has steadfastly resisted the plan. Catalonia accuses its neighbour of hoarding water for unsustainable developments, such as a “European Las Vegas” with 70 hotels, five theme parks and several golf courses planned for a desert region.

Spain's central government has reminded the regions that, under the constitution, only it can authorise any changes in the course of rivers. It turned down the Segre plan, causing frictions with Catalonia's government. Joan Saura i Laporta, Catalonian home affairs minister, criticised the central government's stance as “frivolous, irresponsible and disloyal”.

Soon after taking power in 2004, José Luis Rodríguez Zapatero, the Prime Minister, scrapped a grand plan by José María Aznar López, his predecessor, to take water from the River Ebro to parched regions such as Valencia, Alicante, Murcia and Almería. There again, the plan was marked by ugly battles. Those in need of water accused those in the north of lacking in solidarity, while they in turn accused their coastal counterparts of wanting to water endless desert golf courses.

The Government's scrapping of the Ebro plan made it difficult for it to agree to Catalonia's plan for the Segre, albeit that was on a much smaller scale. Catalonia is now considering other options, including importing fresh water by boat from Marseille and bringing it in by train from other regions. The region is also building a seawater desalination plant that will produce the equivalent of two months' consumption each year.

Climate scientists give warning that Spain will be one of the countries worst affected by global warming. The strain on water resources is all the greater because most development is taking place along its parched, sun-baked coasts. Environmentalists also claim that at least 20 per cent of water in Spain is lost through leaking pipes.

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