Macmillan

Lucy, from Hull, will run her first marathon on Sunday alongside her dad to raise money for Macmillan Cancer Charity in memory of her mother, Clare, who died from cancer when the teenager was nine years old.

On race day, Lucy will be wearing a Macmillan top with the letters 'MUM' on the back.

Hart's publisher, Pan Macmillan, declined to comment, while Sunak has been approached for comment.

In March this year, in association with publisher Pan Macmillan, the charity sent a copy of a book written by Facebook whistleblower Sarah Wynn-Williams to every MP in the country.

The arbitrator’s ruling doesn’t apply to Macmillan, which published the book on March 11 and now can sit back and collect the sales price on a book that has shot up to No. 1 in the politics and social sciences section of Amazon’s website without needing to do any further PR outreach.