The new Royal arrival made his first public appearance with his proud parents as they left the Lindo Wing of St Mary's hospital in London.

The Duke and Duchess of Cambridge proudly showed the world their baby son, a future king, before taking him home tonight.

They began their new lives as parents, cradling their royal baby and posing for pictures on the steps of the Lindo Wing of St Mary's Hospital in London.

The Duchess held her son first and the couple looked relaxed and smiled broadly as the world's media captured the moment.

William later held his son and walked forward with his wife to answer a few questions. He began by joking: 'He's got a good pair of lungs on him, that's for sure. He's a big boy, he's quite heavy. We are still working on a name so we will have that as soon as we can.'

He added: 'It's the first time we have seen him really so we are having a proper chance to catch up.'

The Duchess said: 'It's very emotional, it's such a special time. I think any parent will know what this feeling feels like.'

Her husband agreed: 'It's very special.'

He added: 'I'll remind him of his tardiness when he's a bit older. I know how long you've all been standing here so hopefully the hospital and you guys can all go back to normal now and we can go and look after him.'

The Prince of Wales had earlier given a hint as to the imminent departure of the royal couple. As he left the hospital, he was asked how his first grandchild was and replied: 'Marvellous, thank you very much, absolutely wonderful - you wait and see, you'll see in a minute.'

The Prince had seen his grandson for the first time when he visited the Duke and Duchess of Cambridge in hospital.

The proud grandfather and his wife the Duchess of Cornwall travelled from East Yorkshire, where they had carried out a string of engagements, to see the baby and his parents.

Charles's first grandchild, who has yet to be publicly named, is third in line to the throne.

Charles's visit followed the other new grandparents, Michael and Carole Middleton, who spent just over an hour with their daughter Kate and son-in-law William.

Mrs Middleton described her grandson as 'absolutely beautiful' as she left the hospital and, speaking about mother and baby, said: 'They are both doing really well, and we are so thrilled.'

The new royal baby - the first Prince of Cambridge to be born for more than 190 years - was delivered yesterday at 4.24pm, weighing 8lb 6oz.

The Duke and Duchess have thanked the hospital staff who delivered their baby, describing the care they and their son received as 'tremendous'.