The Miliband brothers have led very similar lives

The prime minister has put family matters at the heart of his policy agenda and, it seems, his new team.

Most strikingly, Mr Brown has appointed the Miliband brothers - David and Ed - to key posts in his Cabinet.

David, 41, is made foreign secretary, one of the four top jobs in government.

Meanwhile Ed, 37 and only an MP since 2005, is given responsibility for the Cabinet Office, which co-ordinates policy between departments.

Sibling rivalry

The Milibands are the first brothers to sit in Cabinet since Austen and Neville Chamberlain (in fact, half-brothers) in the 1920s.

Both went on to lead the Conservative Party, with Neville becoming prime minister.

Like them, the Milibands' destinies have always been more closely linked than those of most brothers.

Both studied at Corpus Christi College, Oxford, with Ed going on to work as a researcher for Mr Brown and David becoming Tony Blair's director of policy.

The brothers - sons of the eminent Marxist theorist Ralph Miliband - also went on to become MPs at the same age: 35.

However, Ed is three years younger than David was when he was promoted to environment secretary in 2006.

Family/planning

The clannish connections in Mr Brown's government go further.

Ed Balls, the prime minister's long-time economic adviser and right-hand man, gets his first Cabinet post, taking over responsibility for children, schools and - appropriately - families.

Harriet Harman's political connections go back generations

His wife Yvette Cooper - elected an MP in 1997, eight years before her husband - remains minister for housing and planning.

Harriet Harman, who finally returns to Cabinet after a nine-year absence to become leader of the House of Commons, is even more deep-rooted.

Recently elected Labour's deputy leader, she is married to Jack Dromey, the party's Treasurer.

Ms Harman's aunt, the author Elizabeth Longford, was married to Labour Cabinet minister Lord Longford.

But another family quirk lurks in Mr Brown's first government.