The sudden, although perhaps not entirely surprising, departure from Tesco of chief executive Phil Clarke divided opinion.

The sudden, although perhaps not entirely surprising, departure from Tesco of chief executive Phil Clarke divided opinion.

Since Clarke took over in 2011, Tesco’s market share has declined and its stock market valuation has slid by almost £9bn.

News of Clarke’s departure on Monday lifted Tesco’s share price, which must have left a bitter taste in the mouth of a man who has devoted 40 years to the retailer – including many years of success.

Despite the share price verdict some investors continued to back Clarke. Notable among them was David Herro of Harris Associates, the grocer’s seventh biggest shareholder, who professed himself “shocked”.

In Herro’s opinion, Clarke had correctly pinpointed Tesco’s problems and identified the right solutions.

From October, it will be up to Tesco’s new chief executive Dave Lewis to work out what’s wrong and come up with some answers.

He won’t be short of advice. City analysts were quick to make their views known.

Some of their views seemed eccentric it must be said. Bernstein’s Bruno Monteyne, himself a former Tesco executive, suggested the retailer operate three types of shop – Value, Finest and midmarket.

That seems to fly in the face of traditional wisdom and the good, better, best price architecture frequently applied in retail so that most customers are catered for in a single store.

What Lewis needs to bring to Tesco is a clear proposition and sense of purpose. What does Tesco exist to do in 2014 and into the future?

This week it also emerged that Aldi co-founder Karl Albrecht had died. For clarity of purpose it’s hard to beat his approach. He once said: “Our only consideration when working out a product’s pricing is how cheaply we can sell it.”

This single-mindedness made Aldi one of the world’s greatest retailers and one of Tesco’s biggest problems today.

Tesco fended Aldi off for many years, despite being a more complex business.

After Clarke’s exit, the question will be how long the City will give Lewis to restore Tesco’s fortunes in the face of rivals’ ascent.

HSBC’s Dave McCarthy, also a former Tesco exec, thinks it could take five to 10 years to turn Tesco around.

It’s hard to see Lewis being given that long to bring home the bacon – whether Value or Finest.