This £18m Mayfair Pad Is The Most Expensive Flat Per Square Foot (PICTURES)

This £18 million Mayfair apartment in London's Grosvenor Square has come on sale, with the rare achievement of being the most expensive apartment per square foot to be put on sale in Mayfair.

How expensive is it? The apartment is a record-breaking £5,130 per square foot. And for £18 million, you get yourself 3,500 square foot of Mayfair property.

Here's all you need to know about the amazingly plush pad, which is being managed by Wetherell estate agents.