‘Yes, lots of big decisions were taken right here,’ I am told by my guide, who tomorrow will take Princess Anne on the same tour. Princess Anne is probably more au fait with this postcode than me, so won’t need to be told that from the window, you can look down on Henry VIII’s wine cellar, or up at Andrew Lloyd Webber’s penthouse, or across at 10 Downing Street or that clock with the hole in it by the Number Two that marks the time at which Charles I was beheaded (apparently they have to vet anyone who stays in here, lest they take advantage of the vantage point and get a bit Lee Harvey Oswald).