Tesco boss Dave Lewis has been told by MPs that he should explain comments he made which indicated that the problems at 2 Sisters Food Group were contained to just one of its 12 chicken processing factories.

On Tuesday, ITV News and the Guardian revealed the details of an audit carried out by Tesco at the 2 Sisters plant in Coupar Angus, the day after we had uncovered alarming practices at the 2 Sisters factory in West Bromwich.

The inspection was one of a series Tesco instigated following our investigation.

The Tesco inspection team unearthed a series of "major" process issues and gave Coupar Angus, which supplies fresh chicken to Tesco and many other big UK retailers, a 'red' warning.

ITV News understands that Coupar Angus was not the only other 2 Sisters factory to be given a red-rating by Tesco during the series of emergency inspections.

In a debate in the Commons, John Grogan MP, who sits of the Environment Food and Rural Affairs Committee, said it was "extremely worrying" that Tesco knew there were problems at more than one 2 Sisters factory but that its chief executive, at a press conference six days after our original report was broadcast, said: "Tesco didn’t have anything which would indicate that what was seen in West Bromwich was present at any other factory sites."

Mr Grogan added: "I think Mr Lewis has some explaining to do. Why did Tesco not provide this (audit) not just to the public but to the Food Standards Agency (the regulator)?"

The chair of the EFRA select committee, Neil Parish MP, told ITV News he agreed that Dave Lewis "should explain his comments" and added that he is considering calling him to answer MPs questions.

Mr Parish said the select committee would convene early in the New Year and would discuss whether to invite the Tesco chief executive to appear.

He said it was "very concerning" that the details of the Tesco audit at Coupar Angus "was not placed in the public domain" and that it was "more concerning that (the audit result) was not volunteered by 2 Sisters at any point during our inquiry".

Undercover footage at 'Site D' in the West Midlands. Credit: ITV News/Guardian

Tesco says that the inspection at Coupar Angus highlighted “a number of inadequate processes” and that the issues were "addressed immediately to prevent any food safety issues".

A spokesperson for Tesco explained that Dave Lewis’s comments at the press conference related to the fact that his inspection teams had not found any evidence of food safety risks and that the chief executive is not ordinarily told about red-ratings unless food safety breaches are identified.

In that sense the process problems at Coupar Angus were very different to the specific issues ITV and the Guardian uncovered at West Bromwich, where chicken which had fallen onto the factory floor was filmed being returned to the production line.

Tesco says it "works closely" with the regulator and has shared the “key findings” of its inspections with the Food Standards Agency. The supermarket shared the full details of the audit at Coupar Angus the FSA after being contacted by the Guardian and ITV

In a previous statement, 2 Sisters has said: "ITV and The Guardian are referring to standard inspection audits and appear to be trying to damage the reputation of our factories and potentially the livelihoods of 23,000 colleagues by misrepresenting them.

"There is and never was any risk to food safety at Coupar Angus.

"This is using old news to highlight issues which were resolved with our customer two months ago."