Average rents for newly let homes have grown by 3.8% in 2015 to reach £946 per month, according to analysis from Countrywide.
Growth in newly let rents was seen in all regions except in central London where rents decreased by 1.4% year-on-year. Greater London, although still growing, has seen its rate of rental growth halve since the start of the year. The South West has seen the highest rental growth in the UK since the start of the year.
All rents increased by 2.8% overall for the year to June.
The research said sustained growth in rental prices over 2015 has led to record numbers of landlords increasing rents on tenancy renewal.
Some 45% of tenants renewing their tenancies had rent increases in August. In the London and the South East markets, more than half of tenants renewing faced higher rents.
Rents have grown throughout 2015, driven by a lack of homes available to rent and high levels of tenant demand.
The total number of homes advertised to let was down by 8% in August compared with last year, whereas the number of registered applicants was up by 4%. With fewer options available for tenants looking to move, those choosing to renew their tenancy are more likely to see their rent increase.
Johnny Morris, research director at Countrywide, said: “Falling numbers of homes available to rent and increasing demand from tenants have been the defining features of rental market so far in 2015. Competition for rented homes has intensified and led to accelerating rent growth. Nine tenants are now registered for every home available to rent, up from 7.5 in August last year.”
Morris said the pressure on rents and increased competition for homes on the market has led to more renewals, and the rental growth South outside of London is being fuelled by more Londoners leaving the capital and looking for more affordable markets in the commuter belt.