Knight Frank says prime central London rents have fallen on a quarterly basis for the 28th consecutive month - a record.
The agency measures the past quarter’s rent levels each month, hence the record; however the agency insists that the balance of power is starting to tip back in favour of landlords as levels of new supply moderate.
It says the number of properties listed for rent in prime central London in the final three months of last year was 19 per cent lower than the same period in 2016 and was the lowest quarterly figure since the first quarter of 2015 according to Rightmove data.
Knight Frank also says there was a 17 per cent rise in the number of new prospective tenants that registered in the final quarter of last year compared to the same period of 2016 in prime areas of London.
Looked at on an annual basis, there was a 0.6 per cent average annual decline in rental values in prime central locations for property between £750 and £1,000 per week compared to a much sharper 4.5 per cent fall for property between £1,000 and £1,500 per week.
In the super-prime lettings market - an even more expensive sector - the agency claims there is also anecdotal evidence that more tenants are putting a clause in their tenancy agreement to give them the first right of refusal to buy at the end of the tenancy in a so-called “try-before-you-buy” agreement.