The deputy leader of Lichfield District Council has announced he is to step down, triggering a shake-up of the ruling cabinet.

Conservative councillor Matthew Ellis told the Express & Star his decision followed his appointment as cabinet member for adult health and wellbeing under the new Tory administration at Staffordshire County Council, adding that it would be impossible to do both jobs at the same time.

Councillor Ellis said taking a back seat at district level will allow him to focus on introducing the “fundamental overhaul” of social services in Staffordshire that he is planning in his new role at County Buildings.

The news has sparked a deputy leadership contest at Lichfield District Council, with two yet to be revealed candidates in the running to replace Councillor Ellis when he officially steps down from the cabinet at the next full council meeting on July 14. The controlling Conservative group will hold a secret ballot to determine who will be appointed in his place.

Councillor Ellis, who is currently portfolio holder for organisational development and the Lichfield Garrick, said he had thought long and hard before making his decision.

“It is with sadness that I am stepping down,” he said. “But I can’t do both jobs at the same time, I think it would be a conflict of interests.”

The councillor did say he would be would be maintaining his interest in the city’s Garrick theatre. “I will be staying on the district council for the time being but on the back benches – other than my role in the Garrick which is more of a front line job.

“The theatre has been very much a changing place over the past two and a half years and I want to continue with it.”

Councillor Ellis’ high-profile new position as social care chief at the county council places him at the head of a department with a £250 million budget and more than 4,000 staff. The role will see him spending 80 per cent of his working time in Stafford.

“It’s phenomenally exciting, and also a bit scary,” he said. “I did think very carefully about whether I could do it alongside my district council role, but even over the last few days I’ve learned that it is absolutely back to back here.”