The UK urges households to stock up for emergencies and attacks

A three-day emergency kit

• Bottled water, about 3 litres a person a day
• Ready-to-eat tinned food and a tin opener
• Cash in notes, coins and cards
• Torch, batteries and a wind-up radio
• Medication and copies of documents

The "Be Ready" campaign begins a three-year drive, and households are told to keep three days of water, food and cash at home.

"How would we cope if the payment systems of the supermarkets went down?"

— Defence Secretary Wes Streeting

Streeting warned that hostile states or terrorists could use cyber attacks to disrupt supply chains. He called the threats "not hypothetical but real", while asking people to stay "alert not alarmed".