Chancellor Gordon Brown was said to be "absolutely delighted" following the birth of his son yesterday.
The Chancellor's wife, Sarah, gave birth to the child at an Edinburgh hospital yesterday morning.
Both Mrs Brown and the child, weighing in at 8lb, were said to be doing well.
It is the second son for the couple, who have been married for six years.
Big brother John, two, has visited the new baby, who made his entrance at 9am at Edinburgh Royal Infirmary.
The Browns' first child, Jennifer Jane, died aged 10 days after being born prematurely in 2002.