The £263m accounting scandal might, in the long run, not prove to be the most important black hole CEO Dave Lewis has to fix if he is to succeed in turning around Tesco.

There have been two other things that have gone missing from Tesco stores across the UK in the months preceding his arrival: enough staff on the front line and availability of the key products consumers want.

So despite today’s profit warning seeing Tesco shares, initially at least, on the end of another hiding, Lewis’ announcement that the retailer has hired 6,000 extra staff to ramp up service and availability in the run up to Christmas, was good news not bad, even if it did wipe a huge chunk off the profits analysts were predicting.

Even more crucially, Lewis has vowed that these moves to give Tesco’s stores the ammunition they need in terms of manpower will not be a temporary crisis measure to see Tesco over Christmas, simply to be clawed back as it slips back into its old ways in January and February.

If the Tesco boss needs reminding how crucial it is to stick to his guns on this point, he need only look back two years ago, to when predecessor Philip Clarke announced he had spent £200m in a six month period to September 2012, employing 8,000 new full time employees.

Clarke back then had already identified the problem of slipping standards of service and its knock on impact on availability but as he found himself pulled from pillar to post with the different challenges faced by the supermarket giant - not least of which was how to safeguard shareholder margins - he was unable to see the job through.

So while Tesco’s staff will no doubt welcome his comments today, Lewis will have to succeed where Clarke failed when the shareholders start screaming for blood, which could be as early as 8 January, when Tesco announces more on its strategy for a reset of the business, after what looks like being a brutal Christmas trading period.