DONALD Trump suggested building an enormous wall across the Sahara to solve Europe’s migrant crisis, a Spanish politician has claimed.

Spain's Foreign Minister Josep Borrell, a former President of the European Parliament, said Trump insisted his Mexican barrier idea would work for Europe as well.

Such a wall would probably span about 3,200 miles and, based on the costs of the proposed wall in Mexico, cost around £85billion, involve 90,000 plus workers and take three-and-a-half years to build.

But while these numbers are epic enough, constructing a wall would more likely than face teething problems - not least shoring up its foundations in shifting sands.

The respected Spanish politician did not reveal when the controversial US leader allegedly put forward his radical migration solution.

But diplomatic sources suggested it was in June when he flew to the States in a trip coinciding with the visit to the White House of the Spanish King and Queen.

Mr Borrell made the claims during a lunch in Madrid organised by prestigious cultural association Club Siglo XXI.

Spanish daily El Pais reported Mr Borrell as saying he had made it clear he disagreed with Trump’s diagnosis but insisted a policy had to be put in place to deal with the fact Africa would double its population in the next 20 years.

Mr Borrell also took the opportunity at the event in Madrid to attack Italy’s right-wing Interior Minister Matteo Salvini who made his mark in the job by turning away a boatload of more than 600 African refugees in June and leaving Spain to pick up the pieces.

Spain has overtaken Italy and Greece as a popular entry point for migrants.

EU border agency Frontex registered 12,500 arrivals in August - with 6,500 of them reaching Spain’s Mediterranean coastline and making the country the main EU port of arrival for migrants for the second month running.

Most of those reaching Spain were from Morocco, Guinea and Mali.

Nearly 30,000 migrants used the Western Mediterranean route in the first eight months of the year according to Frontex, double the figure for last year.

President Trump said earlier this month he was considering using military resources to finish construction of his long-promised border wall instead of relying on Congress to fund it.

Trump has insisted Mexico will pay for the £25billion wall since he started touting the idea of a border block during his presidential campaign.

But Mexican officials have consistently said they will not pay.

The US leader insisted last October a wall would help tackle the problem of heroin flooding into America from Mexico, although critics have rubbished his claims.