It follows the completion of a review of the Novus operation, with chief executive Tim Cullum developing and implementing an agreed growth strategy.
It is understood Turner is to pursue other interests and build on his non-executive roles. He's currently non-executive chair of The Liberation Group and Barburrito, the Mexican chain.
Turner said: “Novus has some of the best bar and late-night sites, and has started an exciting £20m capex programme to reposition and enhance key elements of its businesses. I wish Tim Cullum and his team at Novus every success as they deliver on this strategy.”
Cullum said: “I would like to thank Graham for his contribution and advice during his tenure and wish him well as he develops his non-executive portfolio.”
Novus is undergoing a two-year estate refurbishment programme.