Mr Karasavvas said: “We have seen more and more landlords questioning their profit margins with more asset stripping and placing lower yielding properties on the market.”
Landlords are also selling properties with poor energy efficiency ahead of the Government’s planned introduction of minimum Energy Performance Certificate requirements for the private rental sector, he added.
“We expect more landlords to follow suit as the profit reduces and cost of borrowing rises due to high rates and high fees,” Mr Karasavvas said.
Before 2017, landlords who owned properties in their own names could deduct all of their mortgage interest costs when calculating their profits for income tax purposes.
This tax relief has since been phased out.
Since April 2020, unless they own properties in a limited company, they can deduct only 20pc of their interest costs. This means that they will continue paying the same amount of tax even as high mortgage rates erode their profit margins.
Landlords in the capital are particularly exposed because high house prices mean rental yields in London are much lower than across the rest of the country.
In the South East, where rental yields are also low, landlords made up 10pc of all properties listed for sale, the second highest rate in Britain.
The share of landlord sellers in London has declined from a peak of 30pc during the pandemic property boom, as falling property prices and capital gains tax rises start to deter sellers, but the numbers are still up by nearly a fifth compared to the start of 2019.
Crucially, many of the landlords selling now are bringing properties to the market because they can no longer afford them, rather than because it is an opportune time to sell.
Imran Khan, chief executive of Property Loop, a London lettings agency, said: “Many landlords are struggling to make ends meet, leading to a concerning exodus from the market.”
Craig Fish, director of Lodestone Mortgages and Protection, said high rates meant some buy-to-let properties in the capital have become loss-making.
Rent growth across all lets hit a new record high for the eleventh month in a row in March, according to the Office for National Statistics.
