One in four younger renters are thinking of moving away from London because of the high cost of accommodation.
The average weekly rent in London has risen to £553, according to the latest data from Foxtons, with an average of 29 would-be renters competing for each of the 23,000 rental properties that came on the market last month.
Supply fell by 18% in September, while demand rose by 18%.
A survey of 1,000 renters aged 25-45 by Pocket Living, which builds flats for first-time buyers, found that 27% of renters were considering leaving London within 12 months, with people in their early thirties the most likely to be looking at moving.