Britain’s biggest retailer Tesco said yesterday that CEO Dave Lewis will step down next year, after declaring his mission “complete” to turn around the group’s fortunes.

Lewis, who has axed thousands of jobs in a radical overhaul of the supermarket chain since arriving five years ago, is leaving for personal reasons and will be replaced by Walgreens Boots Alliance executive Ken Murphy, Tesco said in a statement.

Former Unilever director Lewis was parachuted into Tesco in July 2014 to help turn around the group, which

at the time was mired in an accounting scandal and fierce competition in home market Britain.

“My decision to step down as group CEO is a personal one,” he said in a statement alongside the publication of the group’s first-half earnings.

“I believe that the tenure of the CEO should be a finite one and that now is the right time to pass the baton.

“Our turnaround is complete, we have delivered all the metrics we set for ourselves. The leadership team is very strong, our strategy is clear and it is delivering.”

News of his shock exit shocked investors, but shares nevertheless rose two percent to 244.30 pence on the London Stock Exchange, which was generally lower.

“Tesco has dropped a bombshell on investors by announcing the departure of boss Dave Lewis,” said Markets.com analyst Neil Wilson.