It’s 1937. You are packing the car for a trip into the countryside. The fold-up gramophone is on the back seat, beside the primus stove, the spare cans of petrol and the rug. All that is left to sort out is the picnic. The haddock mousse is ready, the iced claret is in the new Thermos, but the casseroled grouse and macedoine of vegetables still need to go in the hamper.

The recipes come from your new book, Mrs C S Leyel’s Picnics for Motorists, published in 1936. Mrs Leyel, a radical herbalist who challenged the cooking conventions of her time, was a clever woman. She had recognised a niche in the culinary market created by the new craze for motoring in the 1930s. Austin Sevens rolled off the Longbridge production line, while Morris Minors chugged out of Cowley. Driving was no longer only for the wealthy; a prudent factory worker could just about afford a new car, though it would cost the equivalent of a year’s wages. Those less careful with their pennies could take advantage of the burgeoning second-hand market.

By 1939 there were two million vehicles on the roads. The boom was fuelled by a desire to go on day trips and touring holidays. “There was a pioneering spirit, even though most motorists probably wouldn’t go further than 50 miles,” says Michael Tambini, manager of the Cotswolds Motoring Museum in Bourton-on-the-Water. Roads were reasonable, though narrow. Speed was sedate. “You might get to 50mph going downhill with a breeze behind you. So long as you didn’t mind not being able to stop very quickly at the bottom.”

When the 1930s motorist did apply the brakes, it was often to picnic at a landmark, in pleasant countryside or by the sea. If they needed advice on a destination they turned to the fledgling RAC and AA motoring organisations, whose employees would laboriously plot them out a route. Between 1934 and 1935 enquiries to the AA rose by as much as 50 per cent, according to Trevor Dunmore of the Royal Automobile Club library in London’s Pall Mall.

The Cotswolds, the West Country, the South Coast, Bournemouth, Sussex and Kent were all popular touring destinations. “Some even ventured to the outlying areas of Scotland,” says Mr Dunmore, “which, given the hardly reliable nature of vehicles then, shows they were a pretty adventurous bunch.”

If the AA and RAC couldn’t come up with a suitable destination, then another organisation had plenty of ideas. Shell Oil, with an eye on its profit margins, launched Visit Britain, an advertising campaign that has become a minor legend. The company trawled art schools for the cream of young talent, commissioning the likes of John Piper, Paul Nash and Graham Sutherland to produce dramatic modern posters of landmarks and landscapes - with no trace of cars, roads or garages. Fine art was plastered to the side of fuel lorries to inspire the passing motorist.

Many of the Shell sites are still great places for picnics. Relax in the Nidderdale moorland of Yorkshire and imagine Graham Sutherland tucking into his sarnies as he painted his whirl of a picture of Brimham Rock. Maybe Clifford and Rosemary Ellis shared a flask of tea as they discussed their image of Chanter’s Folly in Appledore, Devon. Anthony Stuart-Hill perhaps tippled on something stronger while creating his vorticist picture of Mousehole that drags the day-tripper down the hill to the popular Cornish seaside town. Richard Guyatt got to work on Ralph Allen’s fantastical sham castle, which is now on the National Trust’s Bath Skyline walk, and recommended as a good spot for a picnic. And tired backs can still rest against the old stones of Llanthony Abbey in the Brecon Beacons, painted in 1937 by Denis Constanduros. The Shell posters and paintings, 30 of which are currently on display at Charnwood Museum in Leicestershire, meant public recognition for these students, many of whom went on to become major artists.

Another creative genius, though in a very different field, had not yet been discovered. Her name was Elizabeth David and her food writing was to be as radical as Graham Sutherland’s art. She brought the tastes of the Mediterranean to 1950s Britain. She also liked getting in a car and going on a picnic. Mrs David became interested in picnics in the late 1930s after an embarrassing culture clash in the south of France. She had planned an al fresco lunch with some American acquaintances, and the young Englishwoman, in love with simple French food, spent a delicious hour shopping for snacks and “yards of bread” in a market in Marseille. But, on arrival at the picnic site, the Americans looked pityingly on their “shameful bundles” of market fare, the dried-up salame and “squalid mess” of anchovies. They had come prepared to barbecue. Out of their car boot came a hatchet to chop off olive branches for a fire and “out of their baskets (they) produce cutlets, potatoes, bacon, skewers, frying pans, jars of ice, butter, tablecloths”.

The coup de glace was ice cream in a Thermos.

Mrs David, driven to philosophise on the ideal picnic, agrees with Henry James’s opinion that it should be “not so good as to fail of an amusing disorder, nor yet so bad as to defeat the proper function of repasts”.

Amusing disorder, by the way, requires china plates and glasses, a capacious hamper with “an aura of lavish gallivantings and ancient Rolls-Royces”, a spirit lamp and a tin of Nescafe. An admirer of Mrs Leyel, she nevertheless warns that “elegant foods such as foie gras and lobster patties should be excluded as they seem to lose their fine lustre when eaten out of doors”. So ditch the casseroled grouse and accept her advice that “the simpler charms of salame sausage, fresh cheese, black olives and good French bread are enhanced when they are eaten on the hillside or the seashore”.

Other suggestions include chicken with mayonnaise, steak and kidney pudding or spiced beef - all served cold. Hard-boiled eggs are “time-honoured picnic fare”. For desert Mrs David opts for “a slab of the dryest bitterest chocolate available” followed by apples, figs and apricots, which all travel well. Drink-driving was clearly not an issue back then. Mrs David recommends “a stout red wine such as a Macon or Chianti which cannot be unduly harmed by the journey in the car”. Pimms No 1 is excellent for a hot day, though don’t forget the cucumber, lemonade, oranges, mint, borage and a Thermos of ice. (The Americans did have an influence after all.) So it’s a Bank Holiday Monday in 1937. The Austin is packed, but the destination is not yet decided. Elizabeth David’s first articles are appearing in print, but her pine-scented Mediterranean shores are still off the map. However, the Cotswolds are not. Why not try Bourton-on-the-Water, painted for the Shell series by Clive Gardiner in 1932. People came here in the 1930s, says Michael Tambini of the Motoring Museum. “They came from the Midlands cities for fresh air and a glimpse of the countryside. They picnicked on the green and paddled in the river that runs through the middle of the village. They still do.”

The Visit Britain exhibition is at Charnwood Museum until August 30. Tel 01509 233754