Research from London estate agents James Pendleton shows there are no new build houses available to families at that price level in eight of London’s 32 boroughs.
In other boroughs there are only a handful. Lewisham, Southwark and Barking have just three each, while Greenwich and Wandsworth have just four.
There are just 603 for sale London-wide with Croydon boasting the most (59) followed closely by Richmond upon Thames (57).
In fact, houses account for just 2.7% of London’s new build property stock below £600,000, so families wanting to take advantage of the scheme are limited to flats.
Lucy Pendleton, founder director of James Pendleton, said: “We know that house prices are overinflated in parts of the capital, but this research really highlights the scale of London’s property crisis for families.
“This research shows that, for those among them who need a leg up, a quarter of the capital is off limits.
“With houses making up such a small proportion of London’s new build property stock below the Help to Buy threshold, the reality is that families will be forced to stay in cramped and uncomfortable accommodation.”