Donald Trump's State visit to the UK later this month is set to reignite his extraordinary legal battle with the former British spy who claimed that Russia possessed compromising sexual material on the US President.

Christopher Steele, the ex-MI6 agent behind the incendiary dossier, was awarded more than £600,000 in costs against Mr Trump after the President's unsuccessful attempt to sue him over what he insisted were 'shocking and scandalous' false claims.

The costs, which were awarded to Mr Steele's company, Orbis Business Intelligence, at a High Court hearing in April, have yet to be paid and are rising daily.

They will have increased by a further £2,000 by the time Mr Trump touches down in London.

King Charles and Queen Camilla are hosting the President and his wife, Melania, at Windsor Castle between September 17 and 19, with a State banquet as the glittering centrepiece.