Take a bow: Azzam-World's largest yacht

It is the largest private yacht ever built and is set to launch a new round of one-upmanship among the world’s super-rich.

At 590ft, Azzam is 57ft longer than Russian oligarch Roman Abramovich’s superyacht Eclipse.

The Chelsea owner’s vessel had been the world’s biggest yacht – until Azzam’s launch in Germany yesterday.

For the playboy who has everything: Azzam the £400m superyacht blows everything else out of the water

Ownership of the £400million craft is shrouded in secrecy but it is rumoured to have been paid for by a member of the Saudi royal family, Alwaleed Bin Talal Alsaud.

Longer than 12 double-decker buses, not only is Azzam the biggest superyacht, it is also expected to be one of the fastest. The 94,000 horsepower vessel could reach speeds of more than 30 knots, or 35mph.

It was designed by Nauta Yachts and constructed in Bremen by Lurssen.

Little is known about the interior of the yacht, which will require a staff of 50 and will be delivered to its owner later this year but  it is likely to match the luxury of Abramovich’s Eclipse, which features an armour-plated master suite, two swimming pools, two helipads, a hall, a cinema, a mini-submarine and even its own missile defence system

Longer than some cruise ships: Azzam is described as the ‘most complex and challenging yacht’ ever built

No expense spared: New super-yacht Azzam has taken one year to design and three years to build

Abramovich has owned Eclipse, which is valued at £740million, since it was launched in 2010. It took the title of world’s biggest private yacht from the 454ft Rising Sun, owned by American businessman Larry Ellison, which in turn took over from the 414ft Octopus, owned by Microsoft co-founder Paul Allen.

Prince Alwaleed, who is said to be worth around £10billion, already has Nabil, a yacht formerly owned by Saudi Arabian arms dealer Adnan Khashoggi, in his fleet.

Azzam’s design suggests it has been built for a buyer in the Middle East as it has about 50 suites but no large open spaces on deck, said TheYachtPhoto’s Peter Seyfferth.

‘I have never seen an Arab-owned yacht with big parties and girls round the pool like the Russians have,’ he said.

‘It is unlikely it will leave its dock very often. It is more of a question of prestige, to have the world’s largest yacht.’

Helicopter lands on world’s largest yacht, Azzam

You wouldn’t want to turn around in a hurry: Azzam is 54ft longer than Abramovich’s yacht Eclipse

Abramovich’s yacht Eclipse is smaller but boasts essentials such as two heliports,several jacuzzis and bulletproof glass.