Fewer than 10% of properties in some London boroughs cost less than the capital's average £550,000.
Fixed fee estate agent eMoov.co.uk finds that, on average, 46% of the housing stock listed across the capital is for sale for less than this amount.
However, in Kensington and Chelsea, that figure's six percent, and it's hardly better in Westminster at seven percent. Even in less prestigious boroughs such as Camden, Wandsworth and Islington, fewer than a quarter of the properties for sale are listed at £550,000 or less.
"It's no surprise to anyone that the majority of London is unobtainable to many from a property point of view. However, this research highlights just how out of reach the capital actually is for UK home buyers, even for those with the sizable budget of £550,000," says founder and CEO of eMoov.co.uk Russell Quirk.
"When you talk about the average cost of buying in the capital being over half a million pounds, the mind really does boggle."
Some boroughs, though, do offer hope for those with a budget of more than half a million.
In Barking and Dagenham, for example, 97% of properties cost less than the London average, with Bexley and Havering following at 91% and 84% respectively.
However, thanks to tax changes, concerns over Brexit and other issues, overseas buyers are becoming thinner on the ground. Some luxury postcodes have seen falls of more than 10% over the last year.
Lancaster University's UK Housing Market Observatory report has predicted that the city as a whole could enter a bubble as soon as next year - with prices starting to crash soon after.
Average prices, and percentage of properties costing £550k or under
Kensington and Chelsea (£1,869,491): 6%
Westminster (£1,179,420): 7%
Hammersmith and Fulham (£936,856): 14%
Camden (£1,070,026): 14%
Wandsworth (£714,621): 22%
Islington (£771,391): 25%
Richmond upon Thames (£798,676): 30%
Lambeth (£640,231): 32%
Southwark (£763,789): 32%
Hackney (£573,722): 36%
Barnet (£556,978): 41%
Tower Hamlets (£485,992): 44%
Ealing (£651,342): 46%
Kingston upon Thames (£527,594): 46%
Harrow (£419,834): 47%
Haringey (£579,193): 47%
Merton (£568,302): 49%
Brent (£484,082): 50%
Hounslow (£337,348): 57%
Bromley (£423,725): 61%
Waltham Forest (£406,482): 64%
Enfield (£358,342): 65%
Hillingdon (£416,902): 65%
Lewisham (£410,076): 66%
Redbridge (£399,559): 72%
Greenwich (£523,208): 72%
Newham (£299,722): 78%
Croydon (£308,855): 79%
Sutton (£377,478): 79%
Havering (£326,181): 84%
Bexley (£304,082): 91%
Barking and Dagenham (£246,238): 97%