£225 million superyacht sails into London

One of the world's biggest superyachts - the modestly-named Motor Yacht A - is turning heads in London, after mooring up on the Thames next to HMS Belfast.

Designed by Philippe Stark and built by German shipyard Blohm + Voss, the £225 million yacht belongs to Russian billionaire Andrey Melnichenko.

Measuring 390 feet long, it's believed to be the 21st largest super yacht in the world, boasting no fewer than three swimming pools that create currents to swim against - including one with a glass floor and a disco beneath.

There's also a 'wellness room' for massages and beauty treatments and a helipad.

The 24,000 square feet of living space includes an enormous main deck described as resembling a 'sumptuous artist's loft'. The walls are covered in wood panelling, stingray skin and silver leaf.

At 2,500 square feet, the master suite is larger than most houses. Decorated all in white, it can only be accessed with a fingerprint scan, and has curved panoramic windows and a king-size bed which rotates at the touch of a button.

The yacht features a state-of-the-art safety system and has bomb-proof windows 1.7 inches thick.

With seven cabins, it can sleep 14 people - but has a crew of 42 to look after them.

Melnichenko, 44, made his money through investments in coal, fertilisers and banking. He's worth around £8.6 billion, according to Forbes, making him the 139th richest man in the world.

His 39-year-old wife, Aleksandra Nikolic, is a former model and pop singer from Serbia, who he married in a £5 million, three-day celebration said to feature performances from Whitney Houston, Christina Aguilera and Enrique Iglesias.

The couple, who have one son, celebrated their sixth wedding anniversary on the yacht in 2011, with a performance from rapper Snoop Dogg.

However, Melnichenko is believed to be putting the yacht up for sale, after commissioning an even larger yacht.

Sailing Boat A, also designed by Stark and currently under construction by Blohm + Voss, is reportedly costing £313 million and is the ninth largest super yacht in the world at 468 feet long.

It will be eight decks high, and incorporate one of the largest single pieces of curved glass ever made, at 193 square feet.