The ARLA Propertymark report said the number of letting agents confirming landlords hiking rent costs for tenants rose to 35% in August – the highest level since July 2015, when 37% flagged an increase.

The figure has risen dramatically since last August, when 27% of agents witnessed rental increases.

Meanwhile, the number of properties managed per member branch decreased marginally in August, to 189 – down from 192 in July. However, this is higher than August 2016 when the figure was 183.

Demand from prospective new tenants increased to 72 in August, from 70 in July.

In August, the number of landlords selling their buy-to-let properties remained the same as May, June and July this year, with an average of three for sale per branch.

David Cox, ARLA Propertymark chief executive, said: “This month’s findings paint another bleak picture for tenants. In November last year, only 16% of agents saw landlords increasing rent costs, but that figure now stands at 35% – which is likely to continue rising.

“Landlords have had a rough ride at the hands of policy changes at government level, and it’s becoming clear that these additional costs are now being passed onto tenants.”