Average residential rents fell by 4.3% around the UK last month, according to new figures from haart.
The agency chain says that typical rents (including London) stood at £919 a month for May, down some 4.3% on April.
Rents outside London did rise, but only by 0.7% to £791 over the same period. Rent rises on the whole have been slowing down steadily since the start of the year.
The number of new applicants looking to rent with haart continues to increase, with as many as seven people chasing every available property in certain parts of London and the South-East.
Andrew Benn, managing director of haart Residential Lettings, said: “After the record rises we saw in 2011, rents have been slowing down steadily in recent months.
“At the same time, we are seeing long-term tenancies becoming commonplace, so while landlords may not achieve the same rents as previously enjoyed, they are benefitting from the security of tenure and with it minimising the potential for expensive void periods.”
Meanwhile, the firm says the number of people applying for buy-to-let mortgages has reached an 18-month high.
The percentage of buy-to-let mortgages processed in May reached 19.6%, or one in five, of all mortgage applications processed by the company.
Two out of three landlords are now choosing fixed rate products, with over half choosing two-year deals.
David Miles, managing director of haart Financial Services, said: “With the base rate continuing at a record low, more people than ever are choosing buy-to-let property as an alternative to other forms of investment, driven in part by the healthy yields they can achieve.
“This is being helped by increased competition between lenders and with it an ever-growing availability of products for this particular segment of the market – something which we as a company certainly welcome.”