You may have been eating Findus horsemeat lasagne since last summer

The company said it was “sorry that we have let people down” and confirmed it carried out a full product recall on Monday, two days before DNA tests confirmed that some of its products contained up to 100% horse meat and it alerted the Food Standards Agency.

But it did not respond to claims by Labour MP Tom Watson that it sent a letter to retailers on Monday warning that a France-based supplier had told it there may be problems with raw materials delivered since August 1 last year.

A Findus spokesman said: “At Findus UK our first priority is our customers and providing quality products they can trust.

“But we know that many people have been concerned by the news this week that tests have shown that some of our Findus beef lasagne has been found to contain horse meat.

“We understand those concerns; we are sorry that we have let people down.”

The Department for Education said today that any schools with concerns about food should “contact their caterer or local authority immediately”.

The Findus spokesman added that the firm “do not believe this is a food safety issue” but that anyone who had bought 320g, 360g or 500g Findus beef lasagne packs could call its customer care line on 0800 132584 for advice and a refund.

Agriculture and Food Minister David Heath said people should carry on with their usual shopping habits until they are told to do otherwise.

He told BBC Radio 4’s The World At One that he was “staggered” by the recent findings, but added: “If there is any risk whatsoever, people will be told.”

He said: “The FSA have now asked retailers and processors to test every single one of their processed beef products to make sure they are what they say they are.

“On the basis of that, we should be in a position very shortly to have very clear picture of what is happening.

“But I cannot honestly say at the moment that the content of every burger is as it should be because we haven’t got the evidence to do so.”

He said there was “every probability” that an element of criminality was involved, and food agencies and police across Europe were investigating what had happened.

The Department for Education issued a statement saying that schools and councils were responsible for their food contracts.

A spokesman said: “We expect all schools to ensure they have rigorous procurement procedures in place.

“If headteachers have any concerns, they should contact their caterers or local authority immediately.”

A spokeswoman for the Local Authority Caterers Association (Laca) said: “We are as sure as we can be that this is not affecting the school catering area.”

She added that there were “strict guidelines” around food safety and supplying dinners in schools, including transparency and traceability of ingredient provenance, written into contracts.

Mr Watson, the MP for West Bromwich East, said he had obtained a letter from the company to retailers saying raw materials delivered to a French contractor since August 1 last year were “likely to be non-conform and consequently the labelling on finished products is incorrect”.

The letter, which Mr Watson said was sent to retailers on Monday, added: “The supplier has asked us to withdraw the raw material batches.”

Findus UK tested 18 of its beef lasagne products, made by French food supplier Comigel, and found that 11 contained in the range of 60% to 100% horse meat, the FSA said.

Retail giant Tesco and discount chain Aldi have withdrawn a range of ready meals produced by Comigel over fears that they contained contaminated meat.

Shadow environment secretary Mary Creagh said today that she would not currently eat any processed food labelled as containing beef and urged ministers to give advice to consumers on whether they should do the same.

“We’ve had 10 million beefburgers withdrawn,” Ms Creagh told the BBC Radio 4’s Today programme. “What tests have been conducted on them, if any?

“The big concern for me now is corner shops, schools, hospitals, prisons, public-sector caterers, people who may have these products sitting in their fridges and freezers.

“There’s been absolutely no advice from Government ministers about what people should do.”

Asked if she would eat processed foods from her freezer which are labelled beef, she said: “I certainly wouldn’t, but I’m waiting for the Government, the experts, the scientists, to tell us and issue proper, clear advice for consumers.

“It’s simply not good enough for ministers to sit at their desks and pretend this isn’t happening.”