One square metre of house space in Kensington and Chelsea is 25 times more expensive than the cheapest area of England and Wales, new figures show.
The London borough tops the list for the costliest house price per area, with homebuyers paying almost £19,500 per square metre last year.
By contrast, the amount paid in Blaenau Gwent in Wales was £777, according to the Office for National Statistics (ONS).
Prices in the capital continued to soar far above other regions, with the cost per area almost doubling to £6,639 between 2004 and 2016.
The five boroughs with the steepest house prices per square metre were all in London, with the City of London (£17,371), City of Westminster (£16,246), Camden (£12,671) and Hammersmith and Fulham (£10,718) following Kensington and Chelsea.
Three of the five areas with the lowest cost per square metre were in Wales, with Merthyr Tydfil and Neath Port Talbot clocking in at £917 and £984 respectively. They were joined by Burnley (£838) and Hyndburn (£976) in Lancashire.
The figures showed the north-south gap continues to widen, with prices in the South East (£3,445) almost double that of the North East (£1,271).
The data covers houses and flats bought in England and Wales between 2004 and 2016.
While there was a slight increase (2.7%) in the size of floor space bought, the rise in house prices was the main driver of growth, the ONS said.
Price per habitable room in England and Wales increased by almost half (45%) in the same period, whereas room size only increased by just over 1%.
A room in London cost almost £133,000 last year, almost four-and-a-half times more than those in the North East, with an average of around £29,700.
A boost in the proportion of detached homes purchased, along with a fall in the proportion of flats bought, account for the slight increase in room size.