At 5,250ft, the £5billion project, masterminded by two British engineering consultancies, will be twice as high as its nearest rivals, skyscrapers under construction in Dubai and Kuwait, and almost seven times as high as the Canary Wharf tower in London's Docklands.

Little brother: The Dubai Tower and Prince al-Walid bin Talal, who is behind the scheme

The plan gives the Middle East a clear lead over Asian countries and the U.S., who have vied in the past to construct the world's tallest buildings.

None of the other skyscrapers under construction, including New York's Freedom Tower on the World Trade Centre site, will exceed 2,296ft.

The prince's company, Riyadh-based Kingdom Holdings, has set up a joint venture with the London firms Hyder Consulting and Arup.

Experts say the technical challenges are enormous. Much of the lifting will be carried out by helicopters, which will also be used as commuter transport for builders.

The tower will have to be capable of withstanding a wide range of temperatures, with its top baking in the desert sun by day but dropping to well below freezing at night.

To resist the strong winds prevalent in the area and stop it swaying, giving its occupants a form of high-rise seasickness, it will be fitted with a giant computer-operated damper.

Two "mini-towers" - both taller than Canary Wharf - will be built on either side of the main tower.

Linked to it by elevated walkways, they will anchor it and act as stabilisers.

Until recently, the still-under-construction Dubai Tower was expected to be the world's tallest building.

Plans have changed several times to make it higher, but the final version is expected to be 2,300ft with 160 storeys.