His problems within the party have been exacerbated by a falling out between two of his junior ministers, Henry McLeish and Brian Wilson, who seem more interested in pursuing their private vendetta than working for their boss.

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Julia Donaldson, Jacqueline Wilson, Horrid Henry author Francesca Simon and the authors behind the Rainbow Magic series, all clocked up more than a million loans last year.

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Despite this artifice, Mr Wilson succeeds in recreating a sense of what Henry VIII was like and how power was deployed in his reign.

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Miller, the Middle East expert at the Wilson Center, cites legendary former secretaries such as Henry Kissinger, James Baker and George Schultz as diplomats who were empowered to create the policies that their presidents then implemented.

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