A council tax discount of 75 per cent to landlords of empty and unfurnished properties has been closed by Richmond Council.
The discount was for landlords whose properties remained empty for up to six months, which the Liberal Democrats said had cost the borough £1.2m.
The Conservative council left the discount in place last year but has now voted to remove it.
Lib Dem leader Councillor Stephen Knight said: “The Tory tax loophole for landlords was always unjustified and has cost the council around £1.2m in lost revenue at a time when vital services are being cut back.
“I am glad that the Tories have finally admitted their error and agreed to make landlords pay their fair share.”
Deputy leader of the council Geoffrey Samuel described Coun Knight’s view as “naive” and said it was kept in place to protect tenants from rent increases.
He said: “The Liberal Democrats were always totally naive in their belief that landlords would pay. If they receive an increase in costs, they pass it on to the tenants.
“Unlike the Lib Dems, we care about 14,000 people in Richmond who live in rented accommodation and were not minded to remove the exemption at the outset.
“It has always been my view that we would not remove it in first year but it was high on my list for subsequent years.”