Roberts' departure after eight years with McBride four as CEO has surprised many in the industry, coming just months after the company revealed strong full-year results.
"As CEO, Roberts has done an excellent job and brought on many strong operational managers within McBride, so he's leaving the company in a good position," said KBC Peel Hunt analyst Charles Hall. "It seems he was simply looking for a bigger challenge elsewhere. In many ways, he'd ticked the boxes at McBride and tackled the most immediate issues. He moved it into new markets, turned around difficult figures and brought in more managers."
Roberts had been instrumental in developing the company's business strategy and infrastructure, said McBride chairman Iain Napier. "The board believes McBride's robust financial performance reflects these changes and we are delighted there is now strength and depth in the senior executive management team. The board is confident that they will continue to drive the business forward positively."
Roberts will remain with McBride, where he has a one-year notice period, until the company has appointed a successor or arranged an "orderly handover". DS Smith said it expected Roberts to take the helm there in the first quarter of 2010.
On the back of Roberts' resignation, McBride has promoted group business development director Gary Saunders to the new interim position of group operations director with immediate effect. Saunders, who continues to report to Roberts, has been with the company for four years and previously worked at RHM (now Premier Foods), Sainsbury's and Nestlé.
Last week, McBride revealed it had increased sales 7% year-on-year but that four percentage points of this was due to currency movements. The company said it expected to cut net debt from £82.4m to £65m by the end of the quarter.