Landlords are choosing to invest in their existing properties rather than take on the extra transaction costs of adding to their portfolios, Countrywide claims.

The agent’s Lettings Index for March showed record numbers of landlords remortgaging to release funds for home improvements rather than to trade up.

In the past 12 months, out of the 171,421 landlords who remortgaged their buy-to-let property, 9,523 did so to take money out to spend on their investment. This is up from 8,459 in 2017 and three times more than in 2016, Countrywide said.

Meanwhile, the index showed the average new rent reached £951 per month in March, 1.7% up on the same period last year.

The midlands saw the fastest rental growth, up 2.8% year-on-year to £668, while average rents in Scotland fell for the second month in a row, but the rate of decline slowed in March to 1.5%, leaving average rents at £615.

Johnny Morris, research director at Countrywide, said: “A record number of landlords are remortgaging to release money to spend on their properties instead of trading up.

“The additional transaction costs incurred from the Stamp Duty changes for second-home owners means more landlords are choosing to invest in their properties, refurbishing and improving them and holding on to them for longer to maximise gains.

“Average rents grew in seven out of eight regions across Britain, with Scotland being the only region to see falls.

“Rental growth during the first quarter of this year stands at 2.1%, 0.5% faster than the same period in 2017, as low stock levels continue to drive growth.”