High-density housing is mixed with work and leisure facilities

Prince Charles invited Chinese business leaders and Prince Albert of Monaco on a royal tour of Poundbury, Dorchester.

The village, built on Duchy of Cornwall land in Dorset, was designed by the prince to encourage integrated affordable, social and private housing.

His birthday will also be marked by the Ministry of Defence promoting him to admiral, general and air chief marshal, "to keep rank parity with his peers".

International interest

The MoD said this would mean he had four-star ranking in all three services.

A spokesperson from Clarence House, said: "It will be a normal working day but he will be spending the evening privately with the Duchess.

"People are keen to see Poundbury. It has visitors from all over the world who come throughout the year to see the principle of urban planning put in to practice there, and the Prince is always happy to help show visitors around.

"Prince Albert has heard about it and was interested to see it."