The imminent departure of Will Cavendish as director of health & wellbeing at the Department of Health has caused doubts over the future direction of the government's health strategy.

Cavendish, who was named the top influencer in The Grocer's Power List for two years running, has been promoted to director-general grade, and will move to the Department of Energy and Climate Change from September.

No successor has yet been appointed, the role has not yet been advertised and as yet no-one has been chosen to fill the vacancy in an acting capacity.

Cavendish, who has a PhD in economics, spent less than 18 months in the job, which expanded under his tenure to include tobacco and drugs policy.

As director for health & wellbeing, Cavendish was a key driver of the government's health and obesity strategies, and also oversaw the introduction of the controversial tobacco display ban. Seen as "a man on a mission", Cavendish used his close links with Labour where he served as head of policy in the run-up to the 2001 election to build a unified health strategy.

"Will's legacy was to pull together lots of different threads into one unified strategy and align many different activities," said FDF director of communications Julian Hunt. "This was a difficult thing to do, and he accomplished it well. We're surprised he's leaving so soon given the strategy is still very much a work in progress, but his new job is clearly a great role for him."

Hunt praised the ability of Cavendish to work with industry and said his successor would have to understand that industry engagement was essential to a successful government health strategy.

Industry insiders have suggested the Department of Health may split Cavendish's responsibilities, or appoint a caretaker to the role, given the impending general election.

"With a general election nine months away at most, and a change in direction of government policy very likely, now doesn't seem the time to make a particularly high-profile appointment," said one.