Shoppers queue at a supermarket, as the number of coronavirus disease (COVID-19) cases grow around the world, in London, Britain, March 18, 2020. [Photo/Agencies]

Panic buying by British shoppers escalated on Wednesday with shelves stripped bare by alarmed customers hoarding for the coronavirus isolation, prompting Tesco and Sainsbury's to restrict purchases.

Prime Minister Boris Johnson, who has faced criticism for acting too slowly and too cautiously to tackle the coronavirus outbreak, said on Tuesday that there was no reason to stockpile and that food supplies were safe.

In supermarkets across the land, though, shoppers were spooked. Aisle after aisle were left empty with just ice cream and chocolate Easter eggs remaining at many major stores. Huge queues snaked around some supermarkets on Wednesday, Reuters reporters said.

"It's getting worse," said a source at one of Britain's major supermarket groups.

Sainsbury's is to restrict customer purchases to combat panic buying. Tesco is allowing shoppers to purchase just two packs of certain items such as dried pasta, toilet roll and long life milk.

Britain's big grocers, including market leader Tesco , Sainsbury's, Asda, and Morrisons , along with discounters Aldi and Lidl, have struggled for over a week to keep shelves stocked.