Prince William selling 20% of duchy property for housing and nature projects

But former Home Office minister and a critic of royal finances Norman Baker said the duchy would still be a “royal fruit machine… he pulls the handle and gets a jackpot every time”.

He said that the switch to more housing would not leave the duchy any worse off: “More houses, more tenants, more income,” Mr Baker said.

In the duchy’s new strategy, there will be a greater emphasis on five areas where it is a landowner – Bath, Cornwall, Dartmoor, Isles of Scilly and Kennington in south London.

The duchy has its roots in medieval, feudal land ownership, but it has been having something of an image make-over, with an emphasis on social value, such as providing affordable housing and protecting the environment.

Chief executive Will Bax said: “The Duchy should exist to make a positive impact, particularly in the communities where we can make the biggest difference.”

Prince William has a project to tackle homelessness, Homewards, and there are plans for the duchy to provide an extra 12,000 homes by 2040. About a third of these are intended to be affordable, with an investment in housing of £161m.

There will be £123m for work places and encouraging the creation of more rural jobs and more support for renewable energy.

That includes an expansion of solar panels on rooftops in the south west of England, with the aim of generating enough power for 40,000 homes.

There will be £20m for environmental schemes and reducing emissions, including helping to restore peatlands and biodiversity on its estates.

This change in direction also comes as pressure grows for more transparency on royal finances.

Particularly in the wake of the Andrew Mountbatten-Windsor scandal there have been calls for more financial openness, including about royal property.