Three days

The Be Ready checklist opens: "Being ready for 3 days helps you manage while support reaches those most in need." The same sentence heads the checklist on the main Be Ready page. The period runs through the list. Water is "bottled water for 3 days, 3 litres per person per day for drinking", with more needed for cooking and washing. Food is "non-perishable food for 3 days", with a long shelf life and needing no refrigeration or cooking, such as tinned meat, fish or vegetables, dried fruit and nuts.

Be Ready says doing this "is easier than you might think", and that readiness can be built gradually by picking up an extra item or two when you can. It suggests checking cupboards first, noting what the household still needs including medical supplies, baby formula or pet food, buying missing items during regular shopping to spread the cost, and setting a reminder every six months to check expiry dates.

The British Red Cross frames the same advice as 72 hours. Its preparedness page asks people to think about how the household would manage if services were disrupted for 72 hours and links to its explanation of why the public is being asked to prepare for that period.