The Government needs to prepare to 'divert the nation's resources' in the case of an emergency, a Labour peer has warned
Britons have been urged to stockpile food supplies amid fears the nation will be shut off from the outside world in the event of war.
Labour peer Lord Harris of Haringey, the chairman of the National Preparedness Commission, has warned the UK lacks a a large stockpile of "strategic raw materials" to improve national resilience.
Lord Harris argued that Britain has the "the most open economy amongst the G20" and imports a large proportion of supplies necessary for life, such as food, medicine and key raw materials.
He raised fears the country could be "shut off" in the event of a conflict, with a need to divert existing resources to the military.
His remarks were made in the House of Lords as it discussed the delayed Defence Readiness Bill, which was recommended by the Strategic Defence Review more than a year ago but was omitted from the King's Speech in May.
The Bill would provide powers to mobilise reserves and industry should a crisis escalate into conflict.
Andy Burnham, who on Thursday came even closer to power, wrote in The Times that Britain's first responsibility was "keeping people safe".
Hs said he plans to do this by rebuilding the UK's hard power by bolstering defence, increasing "sovereign capabilities" and reducing foreign dependency in "all our places".
Lord Harris backed the Makerfield MP in a letter, writing that the UK needed to enhance its resilience and begin a "national conversation" around the topic.
He told the Lords legislation should be based on the framework of the Climate Change Act, adding that it should cover a variety of national shocks - such as pandemics, extreme weather and loss of critical national infrastructure.
It should also place a duty on Government departments, public bodies, local authorities, large businesses and organisations to boost their preparedness to a range of threats and emergencies.
Lord Harris said: "We have, after all, the most open economy amongst the G20. Our food supplies, our pharmaceuticals, plus key industrial materials are imported and vulnerable to blockades and embargoes.
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"We need to be ready for those imports to be disrupted or even shut off.
"And in the event of conflict, we will need to be able to divert the nation's resources to the support of our military and homeland defence."
Baroness Neville-Jones, an ex-Security Minister and former member of the National Security Council, said Britain could be "cutting it close" with our national resilience.
"Nato's assessment is that, by 2030, Russia may decide to step up its existing level of aggression in Europe, something which is truly, truly frightening," she said.
She also questioned whether the Bill would involve "some kind of national service" and urged the Government to be "honest with the electorate" about what war readiness really means.
Lord Coaker, Defence Minister, said the Defence Readiness Bill would be introduced in this Parliament, and would make the case for it to be "funded properly".
He added that the "scope" of the bill was still under discussion.
Nato member states have vowed to spend five per cent of GDP on defence by 2035, with 3.5 per cent on core defence spending and 1.5 per cent on national resilience - which could include safeguarding ports, power grids, or improving transport systems.
Defence Secretary Dan Jarvis on Monday said Britain currently meets the 1.5 per cent spending on national resilience, but refused to say if the country would meet the wider Nato targets.
