|Prime Minister - Gordon Brown
Gordon Brown became prime minister in June 2007 at the age of 56, having been the chancellor throughout Tony Blair's 10 years in power.
The two men have been inextricably linked ever since sharing a Commons office after being elected as Labour MPs in the early 1980s
Their relationship changed when, in a much commented on, but never explicitly confirmed, deal struck in a London restaurant in 1994 Mr Brown agreed to give Mr Blair a clear run at the Labour leadership in return for a promise that he would step down and hand over power to Mr Brown at a later date.
Mr Brown, whose history as a Labour activist dates back to his schooldays, was also given unprecedented powers over huge swathes of domestic policy by Mr Blair.
Despite their public togetherness, especially at election times, there were frequent tensions between him and his backers and Tony Blair and his backers behind closed doors.
His decade as chancellor - the longest in modern times - also witnessed a steady transformation in Mr Brown's image from a studious bachelor to a happy family man with two children.