Competition for London rentals is running 40% higher than at this time last year

'It’s a real challenge for renters at the moment,' says Rightmove, 'as there are simply not enough homes available to rent to meet the demand from people enquiring.'

Current growth rates 'cannot be sustained,' says Savills, as its prime lettings index records the highest annual increase since it started in 1979.

'It won’t become a tenants’ market any time soon,' writes Knight Frank's Tom Bill, as the firm's latest PCL index tells of continued double-digit rental growth.