The departure of Clarke, who had been with the company four decades, came as the supermarket battles shrinking market share following increasing competition from stores such as Aldi and Lidl.
Clarke will hand the reins over to Lewis on 1 October.
How I see it
Marc Cohen, director, Kreab Gavin Anderson
Announcing a CEO change is perhaps one of the toughest communications challenges there is. When you are Tesco that challenge gets even tougher.
With this announcement, Tesco had to show progress, while also acknowledging that clearly things were not working and needed changing.
Tesco did very well to communicate the appointment of the new CEO at the same time as the departure; this took much of the possible sting out of the news and helped it focus on the positives.
It also did remarkably well to keep the news quiet and avoid leaks, a sure-fire way to lose control of the story. The stock exchange announcement was confident and to the point, which helped sentiment, and the shares responded accordingly, going up three per cent on early trading.
Press coverage was always going to be mixed and inevitably it would look back at Phil Clarke’s reign, rather than forward. This was unavoidable. But by announcing the new CEO it was able to have something positive to say and made the most of this opportunity.