Thorneycroft had been on leave since February 2009 and hoped to return to work this Spring.
SimplyBiz chairman Ken Davy says: “It is with enormous sadness and a very heavy heart that I have to inform you that Ian Thorneycroft, our much loved and sadly missed managing director, passed away peacefully in his sleep yesterday evening.
“For the last 15 months Ian has fought a heroic battle against a particularly dreadful form of cancer. Throughout it all his positive attitude, humour and determination have been an inspiration to all, not just those of us who had the privilege of knowing him but to the whole of the financial services sector.
“Today’s news coming only a few weeks after Ian and his wife Judith were given the hope that all had been cleared and barely two weeks since that good news was so cruelly reversed is hard for all of us to take or even comprehend. We all have our own very special memories of Ian and he will live in our hearts forever.
“All our thoughts are now with Judith and the family at this incredibly difficult time.”
In November, Thorneycroft wrote a rallying cry to advisers in Money Marketing to bring back pride in the industry as part of a return to traditional values.
Thorneycroft joined financial services in the mid seventies as a trainee manager in Nationwide Building Society, then called the Co-operative Permanent.
In 1993 he headed up the society’s independent financial advice subsidiary and in 1996 he moved to Legal & General to become operations director for the broker division.
After a spell as member relations director of the DBS network, from 1999 to 2002, Thorneycroft was appointed founding managing director of SimplyBiz in 2002.
He was also a director of the Association of Independent Financial Advisers and sat on various RDR committees.
Davy says: “Ian was passionately committed to helping the IFA sector flourish, and as managing director of SimplyBiz he took customer service to new levels of excellence, including endeavouring to ring every single new member who joined.”
Aifa director general Chris Cummings says: “It is with great sadness that Aifa learnt Ian Thorneycroft had passed away. Ian was an outstanding council member and a strong advocate for independent financial advice. He will be missed by all those who knew him and the industry is the poorer for his passing.
“Those who knew Ian well will miss his sense of humour, spirit of adventure, good sense, and his ability to get to the crux of an issue. Our thoughts go out to his family at this difficult time.”