Only nine London boroughs have average rents for one-bed flats below £1,000 per month now, according to the monthly Landbay Rental Index.
This is down from 11 at the start of the year, after Waltham Forest and Harrow climbed into the £1,000 per month group back in spring.
Kensington and Chelsea tops the board for most expensive rents for one-bedroom properties, averaging £2,275. Bexley offers the cheapest average one bedroom rent prices at £791.
A Londoner paying rent of £1,000 a month has to earn £31,200 before tax to avoid spending over half of their net income on rent.
John Goodall, co-founder and chief of Landbay, said: “The city is a victim of its own success – the magnetic draw of its jobs market and its vibrant culture mean that there is a constant supply of people willing to pay to live here.”