More than one in ten rental properties are now let by company landlords, research claims.

Analysis by Hamptons International found the proportion of homes let by a company landlord has been rising steadily since 2016 when the tapered abolition of mortgage interest tax relief for non-company landlords was first announced.

Research based on Countrywide branch activity found that 12% of buy-to-lets are owned by a company landlord, up from 9% in 2015 and the highest level since 2011.

Hamptons International then scaled up the figures nationally to estimate that company landlords now own 641,480 homes in Great Britain.

This is 42% more than in 2015 when 452,600 homes were let by company landlords.

The analysis also found that rental growth has hit its highest level since April 2016.

The average cost of a new let increased to £986 per month in June, up 3.1% year-on-year.

The south-west recorded the strongest rental growth, with rents rising 4.5% annually.

Aneisha Beveridge, head of research at Hamptons International, said: “More than one in ten rental properties are now owned by private companies, an indication that the sector continues to professionalise.

“Increasing taxation for private landlords combined with the growth of the build to rent sector has meant that more companies are letting homes than at any time since our records began.

“London, where landlords tend to have higher levels of debt and often the most to gain from corporate ownership, has the largest proportion of homes let by a company. However, it’s not always more profitable to put a buy-to-let into a company as other associated costs come into play.

“Strong rents in the south drove rental growth in June. Low stock levels, particularly in the south, continue to put pressure on rents. Rents rose in six out of eight regions, with the east and Wales recording small falls.”