Families are being urged to buy one type of food now to prepare for the potential outbreak of World War 3, or other mass disruptions such as cyber attacks, a new pandemic or extreme weather conditions.

In a new security strategy published last Tuesday, ministers said the UK finds itself in "an era in which we face confrontation with those who are threatening our security". Ministers are stepping up calls for the whole of society to become 'more resilient' and plan to carry out a cross-government exercise on how to deal with crises.

The strategy said: "Some adversaries are laying the foundations for future conflict, positioning themselves to move quickly to cause major disruption to our energy and or supply chains, to deter us from standing up to their aggression. For the first time in many years, we have to actively prepare for the possibility of the UK homeland coming under direct threat, potentially in a wartime scenario."

The Government runs a website to prepare society for all sorts of potential national disruptions, including war, bad weather and cyber attacks, called UK Prepare. As part of its list of advice for households, people are being told to buy 'non-perishable foods', such as tinned foods, as well as a tin opener.

This is because tinned foods that do not need to be cooked, like pre-cooked meat, or fruit and veg, will be edible even in the event of a total loss of power which would otherwise stop you from being able to run an oven or microwave.

The advice says: "Non-perishable food that doesn't need cooking, such as ready-to-eat tinned meat, fruit or vegetables (and a tin opener). As with water, how much you need will vary based on your own circumstances. Don't forget food for pets."

The UK Prepare site also urges families to get a battery or wind-up torch and radio, as well as a portable power bank to charge your phone and spare AA batteries. The guidance also urges people to get bottled water, and if applicable, baby supplies.

The government advice adds: "Consider what supplies you and your household might need during an emergency lasting a few days, such as a power cut or water outage, or situations where you are advised to stay at home or to leave your home (evacuate) for safety reasons.

"It can be helpful to keep these items in one place in your home and ideally somewhere easy to find if the lights aren't working - if you are escaping your house due to a fire, you should not take anything with you at all. You could consider keeping items you might need to take with you if asked to leave your home quickly in a spare bag - you might hear some people call this a 'grab bag'."