Peter Benjamin Mandelson, Baron Mandelson, PC (born 21 October 1953) is a British Labour politician who is the current First Secretary of State, Secretary of State for Business, Innovation and Skills, President of the Board of Trade and Lord President of the Council. Together with Tony Blair and Gordon Brown he was a key architect in the rebranding of the Labour Party as "New Labour" and its subsequent victory in the 1997 general election. Mandelson served as Member of Parliament for Hartlepool for twelve years (from 1992), a seat he vacated in order to become a European Commissioner (2004–2008).

He twice resigned from Tony Blair's government while holding Cabinet positions. After his second resignation he served as the European Commissioner for Trade for almost four years. He rejoined the government when he was made a life peer by Gordon Brown and took his seat in the House of Lords on 13 October 2008.

Mandelson was born in London in 1953, where his father was the advertising manager at The Jewish Chronicle. On his mother's side, he is the grandson of Herbert Morrison, the London County Council leader and Labour cabinet minister.