Isaac, who was also an active member of National Pubwatch, died last month after a short illness.
He worked as Wetherspoon’s director of licensing between 1992 and 2005 and was responsible for securing hundreds of licences for the country.
Martin said: “David was instrumental in Wetherspoon gaining more than 200 licences for new pubs at a time when other brewers and pub companies continually opposed our licences and as a result he played a vital part in the company’s success.
“He will be sorely missed and we extend our sympathies to his family and friends.”
A spokesman for Pubwatch said: “David gave many years service to the National Pubwatch Committee where his legal training and experience of the pub trade proved to be an invaluable asset. He was a caring and supportive man who was always willing to do his best for others. He is a great loss to the Pubwatch movement.”