Online estate agents HouseSimple.com found that all these properties were located in London, despite the recent lull in property prices in the capital.
HouseSimple discovered four studio flats that were listed for more than £1m, despite being less than 500 sq ft in size.
The smallest flat was found in Westminster, which was listed for £1.04m and measured just 416 sq ft; a fifth of the size of a singles tennis court.
The most expensive flat for sale was in Knightsbridge, currently listed with a guide price of £4.95m – almost 22 times more than the average UK property.
- Number of flats sold in London falls by 47%
- Average house price in England could hit £1.5m by 2042
- Only 387 properties in inner London are stamp-duty exempt for FTBs
The 10 most expensive one-bedroom flats currently for sale in the UK
The five smallest studio and one-bed flats on the market for £1m or more
Sam Mitchell, CEO at HouseSimple.com, said that over the past few months the London property market had noticeably cooled.
“Affordability has been a major issue for the average buyer, but we have also seen the top end of the market struggle with fewer overseas investors looking at the capital as a safe haven for their money.
“We could well see a further correction over the coming months, particularly if Brexit negotiations don’t make sufficient progress.
“However, though prices in London have stalled for the time being, and foreign buyers are more cautious about investing here, the average price of property in the capital still means it’s one of the most expensive cities in the world to buy.
“These one-bed flats sourced in our research aren’t ever going to be on the radar of the typical first-time buyer.
“They are more likely to be purchased by wealthy business travellers commuting to the capital.”