Tesco, the supermarket giant that has been making further inroads into the eating-out sector, has announced the appointment of former Unilever chairman Dave Lewis as chief executive to replace Philip Clarke from 1 October.

It comes as Tesco, which last year bought restaurant group Giraffe and also has a stake in coffee chain Harris + Hoole, says that current trading conditions are “more challenging than we anticipated at the time of our first quarter interim management statement on 4 June”.

“The overall market is weaker and, combined with the increasing investments we are making to improve the customer offer and to build long term loyalty, this means that sales and trading profit in the first half of the year are somewhat below expectations. The outlook for the full year will be influenced by the extent to which benefits from the investments we are making begin to be seen; by conditions in the overall market; and by any steps that may be taken during the remainder of the year to improve our customer offer further.”

Tesco chairman Sir Richard Broadbent said: “Having guided Tesco through a substantial re-positioning in challenging markets, Philip Clarke agreed with the Board that this is the appropriate moment to hand over to a new leader with fresh perspectives and a new profile. We are pleased to announce today the appointment of Dave Lewis, president, personal Care at Unilever, as our chief executive from 1 October, 2014.  Philip Clarke will continue as chief executive until that date and will continue to provide support to Dave until January 2015. Philip will also remain chairman of our joint venture with CRE in China until that date.

“Philip has done a huge amount to set a clear direction and re-position Tesco to meet the rapid changes taking place in the retail market. He has achieved a great deal across all areas of the business in the face of considerable pressures. The board are deeply grateful to Philip for his contribution to Tesco, over the last four decades, as well as more recently as chief executive.  His has been an outstanding achievement.

“Dave Lewis brings a wealth of international consumer experience and expertise in change management, business strategy, brand management and customer development. He is already known to many people inside Tesco having worked with the business over many years in his roles at Unilever. The board believes that with Dave’s leadership Tesco will sustain and improve its leading position in the retail market.”

Clarke said: “Having taken the business through the huge challenges of the last few years, I think this is the right moment to hand over responsibility and I am delighted that Dave Lewis has agreed to join us. Dave has worked with Tesco directly or indirectly over many years and is well-known within the business. I will do everything in my power to support him in taking the company forward through the next stage of its journey.”

Tesco also owns a stake in artisan bakery chain Euphorium Bakery and last month M&C reported that the company has begun the rollout of its in-store cafe concept.