He says the prime central London market "very much operates according to its own rules" and centres around international capital, though there is a fairly healthy percentage of domestic buyers.

The appeal of London is not just financial, he says: "Purely in terms of numbers, you've got assets which have risen in value very strongly, you've got a fairly transparent legal system, a fairly transparent property ownership system, and on top of that you've got some of the best educational facilities in the world, the shops, the culture and all the other things that bring people to London - a whole cocktail of reasons."

Broadly speaking, Tom Bill says that with regard to properties in the £10-million-plus bracket, there's a mix of buyers, with some UK purchasers, and "a strong appeal for the former Soviet republics and Russia, and the Gulf countries too."

He says that growth in the prime London areas is slowing, particularly at the top end - £10 million-plus - and prices are now going up in the outer areas of the capital, showing double-digit growth there.