Bournemouth

Mostyn served as chairman as the Cherries enjoyed a meteoric rise from the fourth tier of English football and all the way up to the Premier League.

He was given the new role of club ambassador in December when Bill Foley appointed himself as chairman after purchasing the club from Max Demin.

Speaking to the club's official website, Mostyn said: "I have enjoyed every moment of my time as your Chairman and most recently club Ambassador with this remarkable football club, but feel that the time is now right for me to look forward to the next chapter and focus on other projects.

"After such a long time working in the most rewarding role you could wish for, announcing this decision was always going to be a difficult step to take. However, I am leaving with unwavering excitement about the direction in which the club is heading.

"It has been a pleasure to work in my ambassadorial role since last season's takeover, and I am confident that the vision and investment being made by Bill Foley will lead to great things and continued success in the coming years.

Bournemouth chief executive Neill Blake added: "Everyone connected with the football club would like to wish Jeff well for the next stage of his life.

"Jeff has had an impact on the football club that is hard to put into words and it is right that we use this opportunity to thank him for his many years of dedicated service.

"He'll always be welcome back at Vitality Stadium and I'm sure he'll continue to show his support for the club, which he loves very dearly."

Mostyn also served on the club's Community Sports Trust board and acted as an ambassador to several local charities.

After initially leading a takeover of the club in 2007, Mostyn will leave the South Coast club after 16 years of service.