Peter Marks will retire as chief executive of The Co-operative Group next year.

After six years at the helm – and 45 years in the co-operative movement – Marks will step down at the society’s agm on 18 May.

“I am extremely proud of what has been achieved at The Co-op Group over the past five years,” Marks said.

“We have transformed this business while staying true to our roots as a mutual, ensuring that we now offer value with values to millions more customers than ever before.

“Our ownership model means the top management team has been able to take strategic decisions for the long term, in the interests of our members and customers, and I am confident we have laid the foundations for the ongoing success of the group.

He added: “I have a great team around me – one that has been strengthened over the past year as the group has continued to attract top talent across its businesses. Given all we have achieved, it now feels like the right time for me to stand down.

“I know this business will continue to flourish for years to come because of our determination to put the customer at the centre of everything we do and because I leave the group in very safe hands.”

The society said it would now start the formal process for recruiting a successor, which will “involve the consideration of both internal and external candidates”.

Marks joined Yorkshire Co-operatives in 1967 as a management trainee and rose to become chief executive in 2000. He then became CEO of the enlarged Co-op Group in 2007 when United Co-operatives merged with the Co-op Group.