Prime Minister Boris Johnson and former Police Commissioner Cressida Dick during a visit to Metropolitan Police training college in Hendon, north London. Cressida Dick has resigned as Commissioner of the Metropolitan Police Service. (PA Wire/PA Images)

Prime Minister Boris Johnson and former Police Commissioner Cressida Dick during a visit to Metropolitan Police training college in Hendon, north London. Cressida Dick has resigned as Commissioner of the Metropolitan Police Service. (PA Wire/PA Images)