By Jennifer Hill, Personal Finance Correspondent

LONDON (Reuters) - Noon on Kensington High Street: the shops bustle with lunchtime custom, workers flock to sandwich bars and outside the Royal Garden Hotel a scattering of people talk intently on mobile phones, glossy brochures under-arm.

A property auction is under way.

Some are there simply out of interest. But for the majority, the objective is to buy -- all in the space of a few minutes, and with the simple fall of a hammer.

Follow the yellow "Savills Auction Sale" signs and, inside, the grandiose Palace Suite is packed with rows of chairs, at least half of them occupied, while many buyers prefer to stand at the back.

At the front, the auctioneer is in full flow, flanked by eight "spotters" -- there to keep a beady eye on the room for missed bids.

Auctioneer Chris Coleman Smith cajoles the assembled audience. "Come on, you're going to lose it. I can't believe this," he urges them.

Business is not what it used to be. A handful of lots later and two are withdrawn as would-be buyers fail to bid up to the reserve price.

Other lots, though, whip up fierce competition and sell with ease. "First time. Second time. Third and last time." The hammer goes down.