Alan Murdie, a housing lawyer and council tax specialist, said: “From my research, there have only been a couple of cases of successful challenges.”

One of these was successful only after going to the High Court, said Mr Murdie. The other was the home of a wealthy family in London which had been disaggregated because it had separate living quarters for staff.

Mr Murdie estimated that 500 appeals to the tribunal against disaggregation had been dismissed since 2016. “Too many disaggregation decisions have now been made that the tribunal is afraid to overturn one,” he said.

The VOA said it did not have data on specific types of appeal and that the Valuation Tribunal was independent from the VOA. The Valuation Tribunal also said it did not track data on HMO disaggregation cases.

Mr Daniel noted a recent tribunal appeal that he made for a landlord whose property in Peterborough had been disaggregated. “The tribunal said it did not have the jurisdiction to contravene the listing officer. If you don’t have jurisdiction, what is the point of the tribunal?” 

Tenants are normally liable to pay council tax, but tenancy contracts on HMOs often state that the landlord will cover all bills and council tax for the property. This means that landlords must either shoulder the costs or raise the rent.