Aldi is to spend £1.5bn in the next five years, building a new store a week and recruiting 1,500 staff to cope with its ambitious expansion, MD Paul Foley has told The Grocer.

And, in a warning that will send a chill through the big four supermarkets and beyond, he promised this was just the start of a long-term consumer switch to the Limited Assortment Discounters.

"In Germany discounters occupy more than 40% of the market. I can't think of any reason why that wouldn't happen here.

"The credit crunch is an opportunity for us because more people will think about shopping with us but we would be growing anyway," said Foley.

"This kind of offer can't fail," he said, in an exclusive interview. "If you have the best products it is impossible to fail. Value and premium go hand in hand. I don't sell anything you would consider economy.

"There is no one particular area of the country we are targeting - everywhere is fair game. We will open one a week for the foreseeable future. We can do it quicker, cheaper and easier than the supermarkets," he claimed.

Aldi's plans come as the economic downturn became visible in TNS grocery market share figures published this week for the 12 weeks ending 15 June.

Both Aldi and Lidl delivered strong year-on-year growth rates - 21% and

13% respectively. In the case of Aldi, this resulted in a record share of 2.9%.

The grocery market has continued to grow strongly, in value terms, but the 6% year-on-year growth hid static volumes.

"Food inflation is running at 6% in real terms. The industry has ground to a halt," said Mike Watkins, senior manager of retailer services at Nielsen. 

The figures show Netto is the worst-performing of the discounters, with its market share slipping by 0.1 percentage point to 0.6% of the grocery market.

Sales at the retailer have grown, however, and Netto claimed its Yorkshire heartland has actually seen 15.8% year-on-year growth, far outperforming the rest of its estate.

Netto MD Richard Lancaster promised further growth: "We are aiming to open a further four stores across the region over the next six months, which will enable us to sustain this level of growth."

Aldi said it will eventually reach its target of 1,500 British stores and is working on opening 227 at the moment.

"What is happening right now is a jolt to people's buying habits to swap grocery stores and to try something new," said Foley.

"It is down to us as to whether we are good enough to keep the consumer but if people believe they can get the same from us they won't go back."