"Brian will be fondly missed by all of us that knew him, and the City of London has lost a true character and pioneer. We also express our deepest condolences to his family," a Winterflood Securities spokesperson said.

The East Ham native and AIM trailblazer began his career in the City as a messenger for stockbrokers Greener Dreyfus & Co in 1953.

He went on to work for stock jobber Bisgood Bishop after two years of national service in the RAF and became a member of the London Stock Exchange in 1966.

He founded market-maker Winterflood Securities in 1988, selling it to Close Brothers in 1993. Eight years before this, he played a key role in setting up the Unlisted Securities Market, which would later become the LSE's junior AIM index.

He retired from the industry on his 80th birthday in January 2017, closing the chapter on a six-decade-long career.

"Today he placed his last trade, a true City gentleman, a friend and mentor to us all, right up to recently," Stacey Parsons, head of fixed income strategy at Winterflood Securities, wrote in a LinkedIn post.

"Rest in peace Mr Winterflood, I am wholly grateful for the opportunities you afforded me and so many others in financial services," she added.

Winterflood was an influential voice in the City. He became chairman of the Gilt Edged Market Makers in 1994 and in 2002 became a Freeman of the City of London as part of the Livery of the Worshipful Company of International Bankers.

He was also known for his charitable work for the October Club, the Stock Exchange Benevolent Fund, Save the Children and the Lord Mayor's Appeal, and was a patron of the Natural History Museum, Museum of London, and The Science Museum. He had aspirations to establish a Stock Exchange Museum in London, which never came to pass.

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