DNA: Analysis of Queen`s reign who changed Britain

Yesterday, news came from Balmoral, Britain, that 96-year-old Elizabeth had died. Shortly thereafter, Elizabeth's private secretary, Sir Edward Young, over the phone to British PM Liz Truss said only this, London Bridge is Down. This is the codeword, after which, when spoken, the whole of Britain is drowned in mourning. This codeword is said when the head of the country dies.