BBC.Metropolitan Police Commissioner Sir Ian Blair has resigned.
Sir Ian, the UK's most senior officer since 2005, has faced criticism over the racism row involving the Met's most senior Asian officer Tarique Ghaffur.
There have also been questions about his handling of events surrounding the shooting of Jean Charles de Menezes by police marksmen.
Sir Ian has denied any wrongdoing over an inquiry into the use of public money to pay a close friend to advise him.