Mr Warwick was chairman and founder of Warwick Butchart Associates, a Financial Planning firm in Cheltenham which he set up in 1981.
He was a founder board member of the Association of Independent Financial Advisers, former president of the Life Insurance Association and director of the Securities and Investment Board.
In 1996, Mr Warwick was awarded a CBE for services to financial regulation and received a lifetime achievement award from Scottish Widows.
Mr Burren, who worked with him as managing director of Warwick Butchart for 14 years, said: "He was very forward-thinking, he suggested licensing advisers and CPD almost 20 years ago, and was very involved in regulatory and industry matters.
"He achieved many things during his time and rubbed shoulders with many people but was always grounded and down to earth. His greatest achievement is the affection of his wife, children and grandchildren."
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He said his favourite memory of Mr Warwick was not a work-related one but rather when the pair attended a dinner with the England World Cup 1966 footballers.
He said: "My favourite memory is of me with him in London at a dinner called 'The Boys of '66' which was a reunion of all the England footballers from the World Cup where Len had been present at all the England games including the final. He was thrilled to meet footballers like Jack Charlton and Alan Ball from those days and I'll remember the enthusiasm and enjoyment on his face. He took that enthusiasm to everything he did."
Mr Burren said the firm had been inundated with positive comments from people who had known Mr Warwick and it would be "a real comfort" to his family that people appreciated his work.
Sue Whitbread, communications director at the Institute of Financial Planning, said: "As an IFP member for over 15 years, our thanks go to Len for the significant part he has played in the development of the Financial Planning profession. He was a true gentleman and will be very sadly missed by all who knew him."

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