A Harpenden hardware store has been caught up in the international ransomware cyber attack.

The attack shut employees at the town’s Jewson store out of the computers and card machines, meaning they had to fill out receipts in ink after adding them up by hand.

In a statement Saint-Gobain, Jewson’s parent company, said: “As with other large companies, Saint-Gobain underwent a cyber attack today. For security reasons to protect our data, the group has isolated its IT system.

“We’re working to resolve this as quickly as possible and we apologise for any inconvenience.”

Workers at the Southdown store also had to use old sliding readers for cards but the company is hopeful it can return to normal this morning.

Customer Steve Gledhill said: “One member of staff wrote out the order while his colleague looked up the prices. VAT was added with a calculator and then it all was totalled up. It was very efficient.

“The credit card facility was down too but they has one of the old credit card machines which took an imprint and then I had to sign. Took me back to the 1960s!”

The government’s National Cyber Security Centre, an agency within GCHQ, said: “We are aware of a global ransomware incident and are monitoring the situation closely.”

The attack also affected the Ukrainian central bank and a Russian oil giant.