Judge who ruled against Mail on Sunday in favour of Duchess of Sussex privacy case once defended the tabloid against Prince Charles

The judge who ruled that the publication of extracts by the Mail on Sunday of a private letter Duchess of Sussex sent to her father was "manifestly excessive”, once represented the newspaper in its defence of a copyright action brought by the Prince of Wales.

As plain Mark Warby, he acted for the tabloid newspaper after it was sued by Prince Charles over its publication of extracts from his 1997 journal on the handover of Hong Kong to the Chinese.

The legal action brought by Prince Charles, the Duchess of Sussex’s father-in-law, in 2006 was in itself a groundbreaking case. The heir to the throne had written a 3,000-word journal on his way back from the Hong Kong handover, under the heading "The Great Chinese Takeaway".

Copies of the journals had been circulated privately to the prince's friends and passed to the newspaper by a disaffected former member of staff. Prince Charles had called the Chinese leadership "appalling old waxworks" and criticised government ministers but the judge in the case was scathing of the Mail on Sunday’s defence and the newspaper lost.

Lord Justice Warby (below), elevated this month to the Court of Appeal, was the most senior media law judge in the country when assigned to the case being brought by the Duchess. He was Judge in Charge of the Media and Communications List from 2017 until his promotion to the Court of Appeal.

Media lawyers credit him as probably the leading expert on privacy law. During his time as a leading QC, he acted in many of the key privacy cases that have shaped the law over the past 15 years, including representing the News of the World in the privacy claim brought by Max Mosley, the world motor racing boss, over allegations he had taken part in a “sick Nazi orgy”.

The News of the World lost the 2008 trial and was ordered to pay £60,000 in a case with far-reaching consequences.

Lord Justice Warby, 62, attended Bristol Grammar and St Johns College Oxford before being called to the Bar in 1981. He was appointed a QC in 2002, before being sworn in as a High Court judge in 2014, after 32 years at the bar.

He was joint head of chambers at 5RB and built up a strong reputation in sports law, specialising in sporting corruption cases. For 19 years, he was chief prosecuting counsel for the horse-racing authority.

Lord Justice Warby, who heard the application over two days at the High Court, said the Duchess had a “reasonable expectation” that the contents of the five-page letter would remain private.