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Tony Blair became Her Majesty's tenth Prime Minister and would end up being one of the most controversial during her reign.
The Queen Mother was one of the royal family's most famous members and helped stabilise the monarchy's popularity. She had seen off the Luftwaffe and Adolf Hitler. She represented not only a country and an empire, but a century of human history.
Elizabeth II's reign has been peppered with personal crises within the royal family, from Princess Margaret being denied her choice of husband to the death of Princess Diana.
The Queen has had 14 Prime Ministers during her reign. Who influences who when it comes to decision making and does the Queen have a favourite?