Lewis, who was parachuted in to head the beleaguered retailer earlier this month, said due to the "complexity" of the investigation into Tesco’s finances after it over stated its half year profit by up to £250 million, it would not be able to say more on the issue before its interim results on 23 October.
"This is a serious issue," he outlined in the email, reported in Retail Week, "and we have seen an understandable reaction from the markets and the media this week.
"Turning our business around will require change in our culture, as well as in our processes and our brand proposition."
The retailer, mired in crisis over the past few weeks, suspended four executives earlier this week pending an independent investigation into its financial reporting led by Deloitte and Freshfields.
The email sent to staff
Thank you for everything you have been doing this week and for your support in what has been a challenging few days for our business.
I want to update you on the steps we have taken since our announcement on Monday, and to respond to some of the questions colleagues have asked me this week.
You will be aware that we have launched an immediate independent investigation. We have asked Deloitte to lead this work, supported by our external legal advisers Freshfields. Due to the complexity of the investigation we do not expect to be able to say much more on this issue before we publish our interim results on 23 October. I hope you can appreciate this.
As I said on Monday, this is a serious issue and we have seen an understandable reaction from the markets and the media this week. I know the last few days have been difficult for us all, but I want to be clear that nothing takes away from the huge amount of passion and expertise that I know exists in this business, or from what I believe we can build in the future.
Turning our business around will require change in our culture, as well as in our processes and our brand proposition. We want to work in a business which is open, transparent, fair and honest. We all expect Tesco to act with integrity and transparency at all times. Our values are what define us, and it is in times of challenge that these values are tested. At this challenging time I commit to you that we will live those values to the full.
Above all, we must get back to doing our best for customers. Despite everything that has been happening this week we have been making progress, and we’re giving a sharper focus to the service we provide by investing in more hours in stores as we prepare for Christmas. You’ll be seeing the results of this over the coming few days.
I am clear that everything we do has to be about giving colleagues the space and support they need to do a great job for customers. This is a time for us to pull together as a total Tesco team, with a complete focus on our customers. The steps we’re taking can help deliver that.
Thank you for everything you are doing and if you have any questions at all, please do get in touch.