Shoppers undertaking last minute Pesach preparations are being advised to check the packaging of Tesco matzah meal after customers found it was not certified for the festival.

Lesley Morris bought two packets at the Borehamwood branch of the supermarket on Wednesday, only to discover when she unpacked them that one was not kosher for Passover. Both packets had been on display next to each other in the store's designated Kosher for Passover section.

Another woman encountered the same problem with her online order from the Borehamwood branch, unaware that only one of three matzah meal types on offer was certified for Pesach. A shopper in Brent Cross also found teh same thing had happened there.

Mrs Roberts, who did most of her shopping for the festival in the Borehamwood branch this year, said she was already in the process of changing her crockery over for Pesach when she "happened to glance at the packet" and was shocked by the label.

"People have already started cooking," she said. "I've spoken to friends and they said they would be very upset."

A Tesco spokesman said: "We do our very best to make sure that our products always match our shelf edge labels.

"We have asked staff to check our kosher goods regularly to ensure this is the case."

An Asda customer who ordered goods online was shocked when the delivery included blue Rakusen's matzah, which cannot be eaten during the festival.

"I ordered them the last week and the week before too, and the same thing happened," she said. "So I doubt they ever got them in or even understand the difference."