It is the ultimate test for anyone attempting to make a good impression on the Queen. Princess Diana is said to have been the perfect guest while former Prime Minister Tony Blair's wife, Cherie, is believed to have fell short after the Queen Mother was said to have been left "mortified" by the lawyer's trousers.
However the wife of the ex Labour leader, 66, has since revealed that their youngest son Leo, now 21, was conceived at the Scottish holiday home to the Royal Family, Balmoral Castle, after she left her contraception at home.
The barrister described how she fell pregnant with their fourth child in September 1999 during the annual Prime Ministerial visit to the 50,000-acre estate in the Scottish Highlands.
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