Hindsight, as they say, is the perfect vision. Sir John remains nonplussed by the endless postmortems. The failure of the company at the end of the 1980s was as much the failure of the Government to control the economy, he says. "If you are going to manufacture something complicated you have got to do it in a world class economy, especially one that controls inflation."
And what of the comments of his successor at Jaguar, Bill Hayden? Earlier this year Hayden described the Jaguar plants as worse than anything he had seen behind the Iron Curtain. Does that hurt? The question, at first anyway, gets a low-key response.
"I can't put any credence on it," says Sir John, hands on stomach, shrugging. "Ford went out of its way to buy Jaguar - it almost knocked the door down. It paid a fair price. It couldn't have got it for any less as there were lots of other companies willing to pay for it. I think the comments are more directed at Hayden's colleagues in Ford than anyone else."
Then he pauses, and, as if thinking better of his own diplomacy, continues: "I never cried for help from anyone. The company was in worse shape when I took it over and I got us out of it. I did not do much whingeing and whining."
Ouch! Few doubt that there is a harder edge to Sir John under the dispassionate civility. If there is a temper, he is careful to lose it only when it suits him. For Sir John, it is said, is one of the more image-conscious captains of industry. Around his office, for instance, are displayed the gongs of a long and successful career, framed certificates of the many awards and honorary doctorates that he has collected. Some might keep them in the loo: Sir John chooses to keep his where employees and colleagues can see them.
And in interview there is the occasional sense that he is rather uneasy and awkward, as if he worries a lot about how he might appear. It certainly cannot stem from any unfamiliarity in dealing with the press. Perhaps, like many high achievers, he is constantly reassessing his own performance. He hints at it later, talking about why he reads military history.
"I happen to believe that this great human movement of which we are part is very resilient; and trying to put your life into some sort of historical perspective as to how you are taking part in this cavalcade is very important. I'm not sure it has given me any deep insight into anything but it is very interesting."
For all the complaints that he is just a marketing man - and only those close to the British car industry, which has been so bad at marketing, could turn that into an insult - he in fact started as an engineer. His father was a garage owner in the Midlands, with a Rootes dealership. John, the younger of two sons, would work under the cars for pocket money as a teenager. By his own admission he swiftly realised, however, that he was better at selling them than repairing them. It is a judgement that many feel can be applied equally well to most of his career.
Ignoring his mother's hope that he would become a concert pianist - her father, a musician, had taught the young Egan how to play - he graduated with a degree in engineering from Imperial College in 1961 and went straight into Shell as a petroleum engineer.
No one doubts that the young Egan was ambitious. In 1966 he decided that he needed management skills to advance his career and talked himself onto the London Business School's newly formed MSc business studies course. Fellow students included David Elton, director of Ultramar, Derek Lewis, chief executive of Granada, and James Arnold-Baker, managing director of BBC Enterprises. Sir Terence Burns, permanent secretary to the Treasury, was a lecturer.