Popular snacks from the British company, including Skips, Nik Naks, Hula Hoops, McCoy's crisps and KP Nuts themselves, are a staple in British grocery stores, but their presence on shelves may be in question.

According to messages sent to local shops and published by industry news outlet Better Retailing, deliveries could face delays and cancellations up until "the end of March at the earliest".

"At this stage we cannot safely process orders or dispatch goods," the letter from KP Snacks explains.

A company spokesperson has confirmed to Sky News that KP discovered a ransomware attack on Friday 28 January.

The warning message, sent out through groceries wholesaler Nisa, said KP Snacks was going to limit the size of orders to retailers so it could "manage what stock we do have".

KP Snacks' statement to Sky News said: "As soon as we became aware of the incident, we enacted our cybersecurity response plan and engaged a leading forensic information technology firm and legal counsel to assist us in our investigation.

"Our internal IT teams continue to work with third-party experts to assess the situation.

"We have been continuing to keep our colleagues, customers, and suppliers informed of any developments and apologise for any disruption this may have caused."

The hackers are threatening to release information stolen from the company's IT systems in order to extort it into making a payment to decrypt its files and get its business running again.

The UK's National Cyber Security Centre warns: "Even if you pay the ransom, there is no guarantee that you will get access to your computer, or your files."