我也沒有標準答案，我覺得這裏No.10 refer to唐寧街10號，又指首相的道歉

10 Downing Street ( [About this sound] pronunciation (help·info)) in London, also known colloquially in the United Kingdom as Number 10, is the official residence and executive office of the First Lord of the Treasury, usually also the prime minister.[2] Along with the adjoining Cabinet Office at 70 Whitehall, it is the headquarters of the Government of the United Kingdom.