The appointment in 1990 of Dennis Weatherstone as chairman and chief executive of J P Morgan, the largest bank in the US by market value, signalled not only radical change for the blue-blooded Wall Street institution but also the start of a new era for financial services.

He remained influential after stepping down as head of J P Morgan in 1994. Weatherstone acted as an independent adviser to the Bank of England and sat on the boards of the New York Stock Exchange (NYSE), General Motors and Merck among others.

The softly-spoken and unassuming Briton from a working-class background was an unconventional choice for J P Morgan, which had typically appointed Ivy League-educated bankers from America’s upper class. He had worked his way up from the bottom, beginning his career as a clerk before becoming a trader, and he lacked the brashness of many of his American peers. Weatherstone spent nearly 50 years at the bank, which later became JPMorgan Chase after merging with Chase Manhattan.

Before becoming Chairman and CEO, he had already set about transforming the commercial lender in his preceding role as president, in which he assisted his mentor and boss Lewis Preston in running the bank. Once in charge Weatherstone accelerated its diversification into a global outfit offering an array of financial services.

As a result, JP Morgan was better equipped to meet the demands of clients who wanted greater access to capital markets through ever more sophisticated funding tools. He also changed the group from a bank reliant on lending profit margins to one which generated most of its profits from investment bank fees and its trading operations. “I think people now recognise that we had to change or perish,” he explained in an interview in 1995.

His influence was not limited to changes within JP Morgan. He was instrumental in bringing about fundamental changes to the banking industry — persuading the US Government to relax strict rules brought in during the 1930s and championing the use of new trading instruments.

Weatherstone was the first banker to persuade the US Government to start to relax the Glass-Steagall Act. Introduced in response to the Great Depression, it prevented banks from also underwriting securities. He argued that such rules limited the ability of US banks to compete internationally. The authorities gave permission for J P Morgan to be the first bank to start to underwrite capital raisings in incremental steps — using the bank as a test case before embarking on a full-scale repeal of the Act.

As chairman of the Group of Thirty’s banking industry report on derivatives, he fended off a government push for greater regulation of how derivatives were used and their trades monitored by putting forward recommendations for how the industry could itself regulate use of such instruments.

Derivatives involve the trading of futures contracts, swaps and options which allowed investors to hedge their risks — such as exposure to currency movements — or to speculate about what would happen in the future. He was particularly good at minimising risk for the bank and its clients despite embracing these new forms of trading and entering new geographical markets. He took the bank into emerging markets but, unlike some of his peers, managed not to incur substantial losses during volatile market conditions in 1994.

The changes Weatherstone introduced continued to have a profound impact well beyond his retirement as banks expanded

further into investment banking, and he can take some credit for the consolidation which subsequently followed across all parts of financial services.

A shrewd man, he was respected by his peers, clients and world leaders alike. His unlikely rise to the top from humble beginnings and his approachable manner made him something of a legend among his staff.