Picnic shopping in London for a summer lunch outdoors

The prospect of a picnic on a day in June is one of the great English traditions, and what could be more emblematic of the romance of it all than that basket of fragrant strawberries eaten outdoors on a day when the sun doesn't go down until nearly midnight?

The English go in for picnics, perhaps because of the climate; they are slavish to the merest hint of fine weather. They've been doing it for decades.

Mrs. Beeton's idea of dining al fesco included: "A joint of cold roast beef, a joint of cold boiled beef, 2 ribs of lamb, 2 shoulders of lamb, 4 roast fowls, 2 roast ducks, 2 ham, 1 tongue, 2 veal and ham pies, 2 pigeon pies, 6 medium-sized lobster, 1 piece of collared calf's head, 18 lettuces. . . ." and so forth.

Today many English picnics consist of nothing more than a sandwich eaten in St. James's Park, watching the swans glide by. There are, of course, still very grand picnics, reminiscent of those voluptuous Edwardian days, the grandest of all, perhaps, at Glyndebourne.

Glyndebourne is the opera festival held near Lewes in Sussex every year. There you can dine beautifully in the restaurant on lobster salad and the like, or more romantically on the verdant lawns. It's one of the quaint sights to see people in evening clothes board the train for Lewes at midday, carrying vast picnic baskets. And although most good hotels will pack you a hamper, part of the fun is shopping for your own food.

Start at Fortnum & Mason in Picadilly where, if the assistants are a little less courtly than they once were, they are still to be found in tail coats and even from time to time, bowing in your direction. Fortnum's has a staggering array of jams, biscuits, caviar, pickled walnuts, cold meats, and salads as well as complete hampers.

Fortnum's, in fact, was the first concern to provide "concentrated luncheons forming a desirable portable refreshment . . . when long abstinence from meals is indispensible." They also have the best coffeecake in town.

When I go to Fortnum's I cut through the back entrance, stopping for an ice cream soda at the fountain or one of the meringue pastries with chestnut cream that looks like strands of pasta, and into Jeremyn Street. A few yards away is Paxton & Whitfield at No. 93. It's been here since 1795 and in 1974 was appointed royal cheesemonger.

Paxton & Whitfield smells wonderful and, many think, offers the finest STilton cheese in the world from its own dairy in Leicestershire. There are hundreds of cheeses, some rare English ones such as blue Cheshire, the great Cricket Malherbie cheddar, excellent bacon and cured ham, not to mention the fresh cream you'll want for those strawberries.

Since no picnic would be complete without the sweetmeats, the place to go is Prestat at 24 South Molton Street. The chocolate fish and mice and then peppermint squares, the bitter mints and handmade chocolates with real fruit and nuts are the best in London. Do not resist the truffles; they are sublime.

You can buy smoked salmon at a number of places, but few are as charming as John Gow, fishmongers at 55 Connaught Street, w2 where the fish is displayed in a markable bay as it has been for decades. Unless you have a place to cook, you may not need any meat, anyone culinarily inclined has to see John Baily & Son at 116 Mount Street to believe it. Nothing much has changed here since 1820 -- long copping blocks, old game bird prints, and the gorgeous displays of game birds with fabulous plumage.

If you do have a place to prepare food, by the way, this is the place to buy ingredients for that picnic pate. The butchers will discuss its preparation with you in detail.

Harrod's Food Hall has fruit and fish, charcuterie and patisserie, but it is the butcher department that takes the breath away. Here is some of the most beautiful art nouveau decor in London. Anyone interested in how food was once served should not miss the William Morris green dining room at the Victoria & Albert Museum, just across the way from Harrod's in Knightsbridge.

Finally, for the bread, it's worth a trip to Chelsea, to Beaton, at 134 Kings Road.Delicious white English bread with a thick and crunchy crust, brown bread and buns are served up by behign white-haired ladies who might remind you of Mrs. Bridges.

Now of course, most of us are unlikely to get to England just for a picnic, fewer still to Glyndebourne whose tickets are rarer than golden caviar. You can , however, do the next best thing, which is to take your English picnic into the backyard, put some Mozart on the phonograph, and dream a little.

Here are some suggestions of what you might have for a real English picnic:

Smoked salmon with very thin well buttered brown bread.

Cold roast chicken with cold roast or jacket potatoes.

Hard boiled eggs.

Pickled walnuts.

Cucumber sandwiches also on thin, buttered brown bread.

English cheddar, Stilton cheese, and if you can find it, double Gloucester, all with biscuits, preferably Bath Olivers.

Lots and lots of the best strawberries you can find and a bowl of powdered sugar to dip them in. To pour over them, heavy cream or clotted Devon cream, sometimes available at gourmet shops.

Homemade fudge.

Plenty of Mozart.