"Uber-prime" real estate still hot in London

Savill's Hewlett said buyers were optimistic the economic cycle would eventually turn and were still more worried about missing out on once-in-a-lifetime opportunities.

"Yes, London is going to have a bumpy ride for two years, but in 20 years time they'll be laughing," he said.

Without a widespread drop in global commodity prices - which could deliver a blow to emerging economies still largely unscathed by the crunch - developers and agents say there is little sign of a slowdown for the super-prime.

And critically, even with the economy on the verge of recession, the situation is different from that seen during the 1990s, thanks to an explosion of wealth that Hewlett compared to the Edwardian era of Rockefeller-like mansions.

"Nothing is totally recession-proof, but that end of the market is reasonably immune, simply because we have never had this explosion of global personal wealth before," said Neil Chegwidden, head of residential research at Jones Lang LaSalle.

"It has been in certain sectors, in certain regions - but it is unprecedented."