The Queen has paid a warm tribute to her son as she toasted Prince Charles's 70th birthday. Speaking at a private family party at Buckingham Palace, the monarch spoke of what a 'privilege' it was for her, as a mother, to honour him on such a momentous occasion.

It is understood that Charles was 'deeply touched' by his mother's words which, in a family not known for its public pronouncements of love and affection, was almost unprecedented. 

She described Charles as a 'dedicated and respected heir to the throne to stand comparison with any in history — and a wonderful father'.

Significantly, she also gave his wife, the Duchess of Cornwall, the highest seal of approval, referring to Camilla by name as the woman who 'sustains' him.

And in a humorous aside she referred to her eldest son as a 'duchy original' – a reference to the organic food line he set up in 1990.

Raising a glass at the black tie dinner, the Queen said: 'It is a privilege for any mother to be able to propose a toast to her son on his 70th birthday.

'It means that you have lived long enough to see your child grow up. It is rather like —to use an analogy I am certain will find favour — planting a tree and being able to watch it grow.

'My mother saw me turn 70, of course. And she was heard to observe that 70 is exactly the age when the number of candles on your cake finally exceeds the amount of breath you have to blow them out.

'Over his 70 years, Philip and I have seen Charles become a champion of conservation and the arts, a great charitable leader — a dedicated and respected heir to the throne to stand comparison with any in history — and a wonderful father.

'Most of all, sustained by his wife Camilla, he is his own man, passionate and creative. So this toast is to wish a happy birthday to my son, in every respect a duchy original. To you Charles. To the Prince of Wales.'