Countrywide says one in every 12 homes that came on to the rental market in 2017 was for sale at some time in the previous six months - showing the huge effect of accidental landlords on swelling the supply of homes to let.
This adds up to 80,000 homes in total and it is the third consecutive year that this proportion has increased although it remains well below the previous peak in 2010 where 11.2 per cent of homes that came onto the rental market had previously been put up for sale.
London is still the accidental landlord capital of the country, the agency says.
In 2017 12.5 per cent of homes coming onto the rental market had previously been up for sale. This is the highest figure since Countrywide’s records began in 2007, surpassing the previous 12.1 per cent peak in 2010.
With a stronger sales market outside the capital, would-be sellers across the rest of Great Britain are far less likely to put their home up for rent - for example, just 5.6 per cent of new rental homes in Scotland had been up for sale.
Compared with traditional landlords, accidental landlords tend to stay in the rental sector for a much shorter period of time.
While the average investor owns their rental property for 17 years, the typical accidental landlord rents out their home for an average of just 15 months. Eighty nine per cent of accidental landlords put their property back up for sale after the first tenant moves out, rather than looking for a new tenant.
“While most landlords are in the business by choice, the last three years have seen an increase in the numbers letting out a property they had previously tried to sell. With mortgage rates remaining low, these discretional sellers can afford to let their home, while they wait and see what the future holds for the sales market” says Johnny Morris, research director at Countrywide.