Aldi has gone on the offensive against Tesco by raising questions over product quality at the UK’s largest supermarket – just weeks after a fellow discounter Lidl stirred up controversy in Ireland by branding Tesco’s new Cash Savers discount range ‘Trash Savers’.

In an interview with The Times, Aldi managing director of buying Tony Baines said a new discount range Tesco is thought to be planning was destined to be a failure.

“They will be able to compete with us on price but not on quality,” Baines is quoted as saying. “For that reason I don't think it will work.”

He added: “You'd really expect a company like Tesco to have its own agenda. It does feel to me that they are really struggling to hold on to their customers. We are flying and believe we're taking more customers from Tesco than anyone else. But surely they must have something better to do than worry about a company as small as us?”

Earlier this month the Grocer reported that Lidl had issued a series of adverts in Ireland headlined ‘Cash Savers or Trash Savers?’ questioning the quality of some Tesco products – a campaign Tesco branded “misleading and selective”.

The new row comes after data from TNS and AC Nielsen earlier this month showed that discounters including Aldi and Lidl are continuing to make inroads into the market share of the UK’s leading supermarkets.