William and Catherine have talked to the press for a moment.
Prince William: "Well, he's got a good pair of lungs on him, that's for sure. He's a big boy, he's quite heavy.
"We're still working on a name so we will have that as soon as we can."
He went on: "It's the first time we've seen him, really, so we're having a proper chance to catch up."
Asked how he felt, he added: "Very emotional."
The Duchess said: "It's very emotional and such a special time and I think any parent will probably know what this feeling feels like."
Prince William added: "I'll remind him of his tardiness when he's a bit older because I know how long you've all been sat out here"
"Hopefully the hospital and you guys can all go back to normal now and we're going to look after him ... "
Asked a question by the waiting media about nappy changing, the prince replied "We've done that already" before Kate revealed: "He's done the first nappy already."