Poundbury is the prince's showcase for "responsible planning"

The Prince gave Rebecca and Antony McDonald and their four children the keys to the home, which is run by the Guinness Trust.

Mr McDonald, 41, a builder, said the family were moving from their cramped home nearby to the house next week.

The Prince said it was an "important landmark" in Poundbury's development.

Modern design criticised

He added that critics had said affordable housing and private housing could not be built together but that this showed "that integrated social housing throughout the development is now well established".

Mr McDonald said: "We have now got four bedrooms and it is going to allow me to get some sleep from now on so we're really pleased."

The Poundbury site, which is still only about a quarter developed, is the Prince's vision for town planning and architecture. He has been critical of much modern design.