Gordon Brown's wife Sarah has given birth to a baby boy who is to be named John after the chancellor's father.

Speaking following the birth, Brown said he and his wife were the happiest people in the country.

"It was great and everything went well, Sarah's extremely fit, she really did extremely well and therefore we feel we must be the happiest family in Britain," Brown said.

"We've had a difficult two years but we've been heartened by all the good wishes that everyone has given us and all the support we've had from this hospital.

"Our baby is wonderful, he's beautiful, he's really full of energy and I think he's going to keep me awake for quite a number of days, weeks and months.

"When we came in yesterday morning we drove across the Forth Bridge, saw the rail bridge at the side at about 6.30 yesterday morning, and we just felt it was all going well and it did go well and we're extremely happy.

"John is quite a well known name for the Browns and it's a pretty well known name in our family, but there will be a middle name to distinguish the baby from the many other John Browns there are."

The baby was born in Edinburgh Royal Infirmary close to the chancellor's Dunfermline constituency.

The Browns' first baby, Jennifer Jane, died of a brain haemorrhage aged just 10 days after being born prematurely in December 2001.

Tony Blair was among the first to congratulate his colleague and friend.

"This is wonderful news. Cherie and I are absolutely delighted," the prime minister said.

"I have passed our very best wishes to Gordon and Sarah. We are delighted that mother and baby are doing so well."

Shadow chancellor Michael Howard said: "I am delighted by the news and wish Gordon, Sarah and the baby every joy."

Liberal Democrat leader Charles Kennedy said: "I'm naturally personally delighted for Gordon and Sarah. I wish them both every happiness with their new son."

And the leader of the Scottish Nationalists, John Swinney, also congratulated the chancellor and his wife. "Despite being political opponents, on days like today we can all share in the joy of a new arrival," he said.

"This is great news and I know that the whole of Scotland will be thrilled. My congratulations and those of the whole SNP go to Sarah and Gordon."