Average rents have fallen for the first time in more than six years, according to a new report.
The average rental in Great Britain for February was £5 cheaper than the same time last year, the Countrywide Lettings Index showed.
The trend is driven by falls in London and the South East of 4.7% and 2.6% respectively, compared with February last year. Rents in every other region of the country have continued to rise.
"Early signs point towards 2017 being a rare year where rents rise faster in the north of the country than in the south," said Johnny Morris, research director at property services company Countrywide.
The slowdown in London and the South East has been attributed to a fall in the number of tenants looking for a home, combined with higher numbers of rentals available.
In Great Britain as a whole, there has been a 5% increase in registered tenants, with every region other than London and the South East showing an increase. In all regions but London, rents have continued to rise, with an average increase of 0.8% year-on-year.
"Falls in London and the South East are small in the context of recent growth," says Morris, noting that rents in these areas are a third higher than in 2007.
A spokesman for the Department for Communities and Local Government said: "This Government is determined to make housing more affordable and secure for ordinary working families.
"That is why we're investing a record £3.15 billion to boost affordable housing across London.
"Our housing white paper also sets out how we'll help those renting, including building more homes for rent and banning letting agent fees."