Million-pound apartment sales in England and Wales have nearly trebled in the past decade, according to research.
Data gathered by Lloyds Private Banking showed 2,967 flats worth £1 million or more were sold last year, a 196% jump from 1,002 in 2006.
Nearly all of the plush properties were based in London (96%) and made up 35% of all million-pound addresses sold in the capital that year.
Westminster is home to the most expensive apartments in the UK, with an average price of £2,215,073, according to Lloyds.
Sales of million-pound-plus flats in London have similarly increased threefold, from 973 to 2,853 since 2006, the bank said.
A spokeswoman said the jump was partly explained by a growing population and increasing demand.
Kensington and Chelsea saw soaring numbers of the luxury spaces being snapped up, where 731 flats sold compared with 357 in 2006, overtaking terraced houses as the most popular million-pound properties.
In up-and-coming Hackney, east London, there were no million-pound apartments sold in 2006. Last year, there were 47.
The figures, taken from the land registry, found the exclusive flats now make up 22% of all million-pound property sales in England and Wales.
Sales of flats worth more than £1 million have grown at a far greater pace than similarly valued detached (up 88%), semi-detached (up 154%) and terraced houses (up 165%) in the past 10 years.
The South East saw 44 such flats sold last year, a considerable increase of the nine bought a decade ago.
Head of Lending at Lloyds Private Banking, Louise Santaana, said: "London dominates the million-pound flat market, with the prime areas of Westminster and Kensington and Chelsea accounting for over half of all million-pound apartment sales in England and Wales.
"A finite supply of land in prime central London combined with a growing population has meant the only way is up, with more and more developers focusing on apartments. In the past decade there has been a large increase in the building of high value apartments in Knightsbridge, West End, Victoria and King's Cross, while Marylebone and Mayfair being the top two locations for most development. With demand still high, there are more in the pipeline."