How big can the discounters get in the UK? That is the £175bn question we are tackling in a special report this week.

The answer is less clear cut than one might think.

With Aldi’s market share closing in on Waitrose’s (or matching it already, depending on whose data you look at), it is tempting to buy into the idea that the discounters’ continued rise is inevitable.

But while Aldi, Lidl and co have undoubtedly created a ‘new reality’ for UK grocers - as we set out in our analysis of Waitrose’s surprise warning about profits this week - they, too, are now facing a new reality.

“I’ve always been intrigued by the two discounters’ status as plucky underdogs in this country. They are anything but”

Julia Glotz, managing editor

Of the challenges ahead, the economic recovery is perhaps the most obvious. As levels of disposable income pick up, the discounters will find it harder to hold on to the bargain-savvy middle-class shoppers they attracted during the downturn. A continued focus on product quality and bold ranging (think Wagyu beef) should help, but the big question remains: how do the discounters stay relevant in less straitened times?

Their growing market share could prove equally - if not more - transformative. Having grown up in Germany, where Aldi and Lidl are the defining influence on the grocery landscape, I’ve always been intrigued by the two discounters’ status as plucky underdogs in this country. They are anything but. Our infographic on their impressive footprint across Europe and the rest of the world drives this home.

Of course, those working in the industry know this already. But as the discounters’ market share starts to rival some of the more established names in UK grocery, their serious corporate firepower will become increasingly obvious to British consumers too. This will bring new cachet - but also new levels of scrutiny.

Brits’ famous love of the underdog could turn quickly, and the discounters will need to be prepared for that.

Reconciling growing market share with underdog credentials will be a tall order for the discounters. But based on their track record to date, you wouldn’t bet against them.