A C&G spokeswoman says Champion had told the lender earlier in the year that he would be leaving but had decided to stay on until this month in order to oversee the restructure at the company which included a move to centralise its mortgage processing systems.
C&G says that Champion will be taking a career break before he decides what he will do next.
The lender confirmed it had already started its search for Champion’s replacement.
Chief operating officer Joy Griffiths says: “John Champion has decided to leave C&G at the end of September after nearly 20 years of service.
“John’s contributions to C&G are many. He joined us in November 1987 and has enjoyed a successful career in a number of roles. Starting out as a branch manager he then progressed on to regional manager, head of branches, director of distribution and ultimately to his current role of intermediary sales director.
C&G has changed enormously over the past few years and John has played a key role in helping to shape and develop the business. He has made a significant and valued contribution to our success.”