‘Don’t you know there’s a war on?” is a regular rallying cry in my household. For the past year, we have been mobilised on the Kitchen Front, making do and mending, battling to reduce our fuel usage, waging war on waste and agonising over whether a journey is “really necessary” before booking a break.

We knew we were not alone on the new front line of frugality, but had never dared dream that the residents of 10 Downing Street might be brothers in arms. At least not until last week, when Pa Broon, on the eve of the G8, enjoined the British public to stop being such a bunch of useless wasters and show a bit of world leadership by finishing up our greens and using leftovers.

It is profligacy at the supermarket and in the kitchen that has incurred the son of the manse’s righteous wrath. Statistics from the government body Wrap (the Waste & Resources Action Programme) recently revealed that almost a third of the food we buy annually in Britain (amounting to 6.7m tonnes, at a cost of £10 billion), and 40% of fruit and vegetables, is thrown away. Each day, Britons throw away 4.4m apples, 1.6m bananas, 1.3m yoghurt pots, 660,000 eggs, 5,500 chickens, 300,000 packs of crisps and 440,000 ready meals. Many of the latter are apparently still in date.

Brown’s ticking-off was music to my ears. For the past year I have been researching and writing a book focusing on how green the British public and its coalition government’s policies were during the second world war. And, in drawing lessons from that period for today, asking why subsequent generations rejected those lessons of frugality to embrace mass consumerism and the idea of products having built-in obsolescence, leaving us now to reinvent if not the wheel, then at least the wheelie-bin recycling cart.

My starting point, way back before the credit crunch bit, was a negative one. I had read in Jane Grigson’s classic, English Food, of how the austerity years had done for the patisserie chefs and master bakers of her northern hometown. How awful, the trencherwoman in me cried, to endure a life with neither doughnut nor éclair!

In the archives of the Imperial War Museum, however, a different picture of Britain emerged. A patched-up, threadbare new Jerusalem, yes, but not a nation of malnourished fatties who were costing their precious health service at least £1 billion (some say £4 billion) annually in obesity-related diseases. Nor a country where the government’s own statisticians said one in five children was overweight.

And the values of the people whose letters and diaries I read there had a specific resonance. At the time, I was both failing to juggle several credit card debts and trying to pursue a greener lifestyle, while finding all the modern manuals for that either offputtingly apocalyptic or plain smug. There was nothing in the wartime manuals advocating providence over profligacy that could not be applied to today’s society, but somehow they did it all with much more conviction.

For the parents or grandparents, who we may have once scoffed at for never throwing away leftovers and hoarding coupons, were, in contrast to us, model global citizens. Their carbon footprints barely left an imprint. They wasted almost nothing; and what they had no use for, they recycled. They dug for victory to grow their own seasonal produce, as more of us are again beginning to do. They abandoned their cars and did not dare light a fire, flick a switch or turn a tap without thinking of the energy consumed.

Theirs was not a disposable culture: they made do and mended. In “the great saucepan offensive”, they salvaged. Decades before No Logo became an international rallying cry, they were pioneering anti-consumerists, dressed in utility clothing, with Winston Churchill leading the way. They did thrift years before it became a fashion model’s fad: the second-hand shop and the recycling bin were their generation’s invention.

The austerity measures to save food, materials and labour not only gave Britain the most efficient home front of any country involved in the global conflict, it also improved the nation’s health. In the period of rationing between January 8, 1940 and July 3, 1954, the weight of newborn babies increased, the life expectancy of non-fighting males went up, we had better teeth, stronger bones and grew taller. And the dietary gap between rich and poor narrowed dramatically, as children, especially those from poorer homes, benefited from the National Milk Scheme, the provision of cod liver oil, orange juice and, in particular (Jamie Oliver eat your heart out), the introduction of school meals, which increased from about 160,000 before the war to 1.6m in 1945, when 40% of children received a subsidised meal providing up to a 1,000 calories a day.

As a child, obsessed by the Ladybird History series, I used to have an annoying habit of sidling up to anyone over 30 and asking them reverently to tell me of life “in the olden days”. Now it is I who am an old bore with my war stories.

When emerald-hued greenies talk ardently of a car-free age, I relish pointing out that of the 2m cars owned in Britain in 1939, only 700,000 were still on the road in 1944. Matt Rudd, the InGear columnist, was talking of “hypermiling” — fuel-efficient driving — last week. “Ah yes,” I sighed. “The RAC issued a manual on that in 1939.” (More zealous wartime motorists, incidentally, experimented with converting cars to gas — which proved as disastrous as biofuel conversion is shaping up to be.)

Recent reports that London’s parks might start growing vegetables remind me of the happy days when pig clubs flourished in Hyde Park, the grassland of Windsor Great Park was the country’s biggest cornfield, and landmarks as diverse as the Albert Memorial, the moat of the Tower of London and the forecourt of the British Museum were all planted with vegetables.

I’ve been trying to live the 1940s dream too, down to having put myself on a clothes rationing allowance of 48 points. I was doing well on 26, until my boyfriend proposed. Now we’re all set for a winter wedding. But will I be able to find the parachute silk for a proper dress? Or be able to justify a lavish points splurge?

But, of course it’s what happens after the wedding that counts. We dream of after the war, or at least the credit crunch, when we might move out of our flat, into a little house with a garden where we can grow our own veg and perhaps even keep a couple of chickens.

Sucking Eggs: What Your Wartime Granny Could Teach You About Diet, Thrift and Going Green will be published by Chatto & Windus in 2009

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