It was no big surprise last week when Tesco ousted its boss, Philip Clarke, as the leading retailer continued to lose ground to the German discounters. The man tasked with reversing the trend is Dave Lewis, ex Unilever, a brand man who has some very tough strategic decisions to make. To understand the scale, 75m shopping trips are taken every week to a Tesco store around the world. But their recent troubles have seen 1m customer visits less per week.