Mark Price is to step down from his role as MD of Waitrose after a 33-year career with the supermarket, the John Lewis Partnership has confirmed.

Retail director Rob Collins has been appointed to take over the role when Price leaves the business on 3 April next year.

Price, who has been in charge of Waitrose since April 2007, is set to take up the role of acting chairman of Channel 4 next year. He has been Channel 4’s deputy chairman since July 2013 and will take over the chairman’s role on an interim basis when Lord Burns steps down at the end of January.

Price said he was set to reach two milestones next year: “the grand old age of 55” and the start of his tenth year as MD of Waitrose. “So, after 33 years with the partnership, I took this as a moment to reflect upon what I would like to achieve in the rest of my career,” he added.

”Leading Waitrose has been amazing and I feel blessed to have been given the opportunity; but I’ve always had in mind that ten years would be about the right length of time to do this. And so I’ve concluded that this is the moment to go and do other things in business, consultancy, writing and lecturing.

I am, of course, just at the start of developing my plans for next year onwards. In addition to continuing as deputy chairman of Channel 4, when I leave in April I shall be working with a major global firm to do client consultancy in the area of employee engagement and I have accepted several invitations to give guest lectures at business schools and universities. I am also writing a number of books.”

Rob Collins has been with the John Lewis Partnership for 22 years, initially with John Lewis in a number of senior roles before moving to Waitrose in 2007 to establish its e-commerce business. In 2010, he was appointed personnel director before taking up the role of retail director in early 2012.

Price called Collins a ”terrific person” and said he ’greatly admired’ his expertise and judgement. “He’s got extensive experience in the partnership and a deep understanding of Waitrose and our values,” he added. “I know Rob will do a fantastic job.”

John Lewis chairman Sir Charlie Mayfield said Collins had been a “central part” of the board’s thinking on succession planning for some time.

“Mark is pursuing new opportunities, but he will remain a passionate advocate of the partnership and its ownership model,” Mayfield said. ”He has had a long and distinguished career with the partnership and his leadership of Waitrose has seen outstanding success. As a member of the partnership board for 11 years and deputy chairman since 2013, Mark has played a key role in steering the partnership and has been a valued and trusted colleague.”

Mayfield added that he had worked with Price to ensure the timing of his leaving was in the best interests of the partnership.

The role of Channel 4 chairman was advertised earlier this month, with a remit to “guide the organisation through a period of substantial change” - a reference to the government’s review of the broadcaster’s funding.