HSBC was the major international bank perhaps least affected by the financial crisis, and by delving through the archives Kynaston gained insight into this.

"Doing a book like this involves plowing through huge quantities of material, and there was one eureka moment for us. There was a minute of the holdings board in early 2006 when there was a discussion about why the HSBC share price was flatlining, despite making record profits and being international bank of the year three years running," he said.

"They debated whether they should follow their rivals and go down the leveraged route or stay with the traditional HSBC model of relying on deposits. They decided not to change. Gosh, didn't that pay off."

Kynaston, who was brought up in Shropshire and is half German, went to Wellington College before obtaining a first class degree in history from New College, Oxford.

Although he is visiting professor at Kingston University, his career has been writing books, mainly as a financial historian. He has produced a four-volume definitive history of the City of London, a history of the Financial Times newspaper and also of Cazenove bank.

"I did precious little economic history at Oxford, where it was mainly high history, political, diplomatic, ecclesiastical and intellectual, to a degree. I come to this as a social historian and amateur anthropologist," he said. Kynaston believed that although HSBC may have been sheltered from the financial crisis, a consequence of it has been a fundamental shift of balance from West to East.

"The West has struggled since 2008. You have unemployment rates in Europe that are appalling, and I think in all sorts of worlds you have witnessed a (Oswald) Spengler-like decline in the West. It was clearly coming anyway, but it has been accelerated," he said.

He also believes the financial crisis has led to Western banks being less dynamic.

"If you look at HSBC, some one-sixth of its workforce now work in compliance. Given low interest rates as well, it is hard to see this is a very dynamic sector."

Kynaston wonders how many bankers can still justify their telephone number salaries when many of the general public think some of them should have gone to jail for crashing the system.

"People are rightly perturbed, offended or amazed by the kind of money that is earned by top bankers," he said.

"In the old days bankers didn't necessarily live on the same streets as ordinary workers but there wasn't this stratospheric difference. I was in hospital two or three years ago for three months and thought then that some of the staff would not be getting paid in a year what a banker would get in a day."

Kynaston believes the general public are not yet agitated enough about inequality - also an issue in China - that the views of French economist Thomas Piketty and others about the subject have gained traction. He cites the recent UK election in which Labour leader Ed Miliband was defeated after highlighting the issue.

"There may be an analogy between the Wall Street Crash of 1929 and the financial crisis of 2008. It took 16 years, in Britain, at least, when more collectivist and egalitarian ideas came to the fore when Labour won the election in 1945. We may be looking at 2025 this time. All is not lost for the left in Britain and across Europe," he said

In the book, Kynaston highlights the role HSBC has played in the Chinese mainland in the reform of the banking system, particularly in training its bankers when Liu Mingkang was chairman of the China Banking Regulatory Commission during the last decade.

One big question is how Chinese HSBC will be in the future and whether it will move its headquarters back from London to Hong Kong.

"For what it is worth, if I had to put money on it, I think they will stay put in London," he said.