Sir David Barclay, the co-owner of the Daily Telegraph newspaper, has died at the age of 86.
Sir David, together with his twin brother Sir Frederick, built up a business empire spanning hotels, retail and media.
His death was announced in the Telegraph, which reported that he died on Sunday after a short illness.
Prime Minister Boris Johnson, a former columnist for the paper, paid tribute to Sir David.
"Farewell with respect and admiration to Sir David Barclay who rescued a great newspaper, created many thousands of jobs across the UK and who believed passionately in the independence of this country and what it could achieve," he tweeted.
The Barclay brothers, who had an estimated wealth of £7bn according to the 2020 Sunday Times Rich List, were known for being media shy and rarely gave interviews.
Born in Hammersmith, west London, in 1934, Sir David was profoundly shaped by his childhood memories of war, and the death of his father when he was 12.
He and his twin Frederick - who was 10 minutes younger - started out as painters and decorators, before moving into property and eventually hotels.
Their success in property and hotels helped them take over Ellerman Lines, a shipping business with interests in brewing, in 1983.
This provided a launch pad from which they would become billionaires.
Hotels, papers and shops
At various times, their hotel portfolio has included a number of trophy assets, including the Ritz Hotel in London, which they sold in March last year.
In 2012, the BBC’s Panorama reported that the Ritz had not paid any corporation tax since it had been taken over by the Barclays in 1995.
At the time, Sir David said they had “acted in a responsible way with regard to taxation and have never been involved in any tax avoidance scheme.”
In 2015, the twins sold off the hospitality group Maybourne, which included luxury hotels like Claridges.
The brothers first ventured into media ownership with their 1992 purchase of The European, a pan-European newspaper that shut down in 1998.
They also bought The Scotsman in 1995 and Sunday Business in 1997.
“After these ventures in the publishing arena, the brothers had nurtured since the 1980s an ambition to own the Telegraph group,” The Telegraph said.
They acquired the Telegraph Group in 2004 for £665m from Canadian media magnate Conrad Black's Hollinger group.
The brothers also had a number of forays into retail, including Shop Direct, fashion retailer Very and delivery firm Yodel.
The pair were knighted in 2000 for services to charity. By this point their foundation was thought to have donated about £40m to charity and medical research.
The notoriously private twins' relationship was the subject of an extraordinary legal case last year, in which Sir David's three sons were accused by his brother of bugging conversations at the Ritz Hotel, which they previously owned.
In its obituary the Telegraph said Sir David had been a voracious reader, obsessed with newspapers, business, economics and politics, and had always said he had been educated at the "university of life".