We knew the Prince of Wales was an inveterate letter-writer. Now Gordon Brown has caught the bug. The PM has been bombarding contestants on The X Factor with missives urging them to rebel against Simon Cowell’s strictures.

Unimpressed by the decadent Strictly Come Dancing, Mr Brown has become fascinated by its ITV rival which he sees as a model for “unlocking potential”. A weekly viewer with Sarah and their two children, Mr Brown has found the time to fire off no fewer than 12 letters during the current series.

Yesterday Spanish finalist Ruth Lorenzo revealed that Mr Brown wrote to her praising her for ignoring Cowell’s instructions to sing in her native language.

Lorenzo said: “He said, ‘Keep singing in English, girl. You’re doing a great job! Going against Simon’. It was great.”

Daniel Evans also received a motivational note that read: “Can I say that the next time Simon says that you are only supported by the over 60s, you can tell him that my wife Sarah and I disagree. Although you would be better off mentioning Sarah rather than me, as she is much farther away from 60 than I am!”

Of course, The X Factor is indebted to Mr Brown for waiving VAT on its Heroes charity single – but does that entitle the PM to become an honorary judge?

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