Britain's Ambassador to the United States, Peter Mandelson, has been sacked due to his close ties with convicted sex trafficker Jeffrey Epstein. This decision followed revelations from Epstein’s recently released "birthday book" and email correspondence, which showed Mandelson's supportive relationship with Epstein.

• Most important fact or figure from the article: Mandelson called Epstein his "best pal" in a letter found in Epstein's "birthday book".
• Key person or organization involved: Peter Mandelson, British Ambassador to the United States; Jeffrey Epstein, convicted sex trafficker; Britain's Foreign, Commonwealth and Development Office.
• Notable detail that adds context: Mandelson advised Epstein to "fight for early release" and expressed disbelief over Epstein's first conviction, stating "It just could not happen in Britain."