Business leader Lord King of Wartnaby, the man behind the privatisation of British Airways, has died aged 87.
Lord King was knighted in 1979 and made a Life Peer in 1983
Dubbed Mrs Thatcher's favourite businessman, he was chosen to prepare the loss-making nationalised flag carrier for privatisation.
He was chairman of BA from 1981 to 1993 and was later given the honour of president emeritus.
Reports said he died peacefully in his sleep at noon at his 2,000-acre estate in Wartnaby, Leicestershire.
Baroness Thatcher paid tribute to Lord King on Tuesday evening.
"John King was an industrial trail-blazer. He was one of a handful of bold business leaders who helped turn round the British economy in the 1980s," Baroness Thatcher said.
"I shall miss him a very great deal."
Lord King began his business career working for a number of small engineering firms as a salesman. Soon he was running his own company, Whitehouse Industries, which managed to prosper through securing defence contracts.
After the war, at the age of 28, he bought Yorkshire-based ball bearing company Pollard Bearings and built it up to be the third biggest UK company in the field.
His numerous business interests included the chairmanship of engineering firm Babcock and Wilcox, as well as posts at British Nuclear Associates, Dennis Motor Holdings and BA.
He has also held directorships at the Daily Telegraph, The Spectator and engineering firm Short Brothers.
In 1979 he was knighted and two years later was appointed chairman of BA by Margaret Thatcher.
Lord King hired Colin Marshall as chief executive and the airline was floated on the London Stock Exchange in 1987. The initial share offering was 11 times oversubscribed.
Other actions taken to turn the ailing airline around included 23,000 job losses and an overhaul of the fleet and route map.
Lord King recognised the importance of Concorde to BA's business strategy and used the charismatic airliner to win business customers by guaranteeing a certain number of Concorde upgrades in return for corporate accounts with BA.
During his reign at BA, Lord King courted controversy with the emergence of Richard Branson's Virgin Atlantic - which posed a serious threat to some of BA most lucrative routes.
When Virgin first came on the scene, there seemed little threat to BA, the established, traditional national carrier, but a bitter battle for customers ensued.
A "dirty tricks" row ended with each suing the other for libel.
Richard Branson sued Lord King and BA for libel in 1992. BA countersued and after the case went to trial in 1993 the court found in favour of Mr Branson and Virgin.
Lord King and BA were ordered to pay damages of £500,000 to Richard Branson and £110,000 to his airline. BA also had to foot a legal bill of about £3m.
He retired in June 1993.