During a 15-month Channel 4 (C4) Dispatches investigation with the Mirror newspaper, tenants of the Royal Lands complained of cases of mold and damp.

Some also complained about a lack of eco-friendly upgrades to their homes and the investigation reportedly found a number of rented properties did not meet minimum energy efficiency requirements imposed on landlords.

They found that one in seven of the Duchy’s 500 residential rental properties they identified have low energy performance certificate ratings.

“Miserably cold”

THE The duchy was established in 1337 and many buildings in the real estate portfolio are over 100 years old.

The Telegraph understands that the Duchy is committed to continually improving its properties and works closely with its tenants to actively address the energy efficiency of properties across the portfolio.

A tenant told the C4 Dépêches program: “It is terribly cold in winter, I can only heat two rooms in my house. The Duchy does not understand.

Another said: “The house is cold and it’s a struggle but there’s nowhere to live here… When the wind blows the curtains start to move.” There is no heating at all upstairs.