Rents have risen widely – but have fallen on both a monthly and an annual basis in London.
Your Move said the falls suggest renters in London have reached an affordability ceiling.
Despite edging back, the average rent in the capital is now £1,280 per month, far higher than anywhere else, including the south-east at £878.
Rents in Wales have risen faster than in any English region, but remain among the cheapest at £593.
Rents crept up in the south-west region to stand at £662, but this figure was 1.5% down year on year.
The data, based on around 20,000 Your Move properties across England and Wales, covers February.