Food & Drink: Who's going to fill the winning roll?: Rosie Millard asks the Sandwich Bar of the Year finalists about the secret of our favourite fast food

It is 8am, and crowds of commuters are pushing out of Croydon station, bound for the suburb's office blocks. Nearby, Raymond Simonds is checking the croissants, cappuccino and orange juice in his Pret A Manger sandwich bar, ready for the day's onslaught.

Meanwhile, in Liverpool's financial district, Juliet Shield is arranging fresh flowers and filtering coffee in Hand to Mouth, the city's classiest sandwich shop. This week, both owners are hoping that their efforts will earn them the title, Sandwich Bar of the Year.

According to Jim Windchip, director of the British Sandwich Association, which has been running the awards for three years, the sandwich market is worth pounds 1.5bn a year, and has the biggest slice of the fast-food market (27 per cent). 'The BSA was set up by members of the industry to control standards,' he says, 'and our awards are to identify and reward those people who are leading the way.'

This year's four finalists - Hand to Mouth in Liverpool, Pret A Manger in Croydon, Chatwins in Crewe, and Philpotts in Birmingham - are all places to make Mr Windchip sigh with pleasure, should he venture in to order his favourite ham and egg mayonnaise on brown.

What distinguishes a truly great sandwich from a merely good one? 'Variety,' says Mr Windchip firmly, 'and depth of filling.' (And hygiene: Mr Windchip has been laid out by a chicken sandwich.) When they are done well, he insists, sandwiches are a brilliant invention: eminently portable, healthy and sustaining. 'Marks & Spencer has even begun to export sandwiches to France: British sandwiches have become extremely chic in Paris. The whole market has changed enormously in the past four or five years.'

'Our image is fairly upmarket,' says Mr Simonds at his franchised Pret A Manger shop, the 24th and newest 'unit' in the London chain. He looks proudly along the gleaming, frosted-glass counter to the gently spinning blades within the juice containers. 'At first, I think we came across here as quite intimidating; you have to remember that even the newsagents flog sandwiches in Croydon.'

He estimates he is now selling 800 sandwiches a day, even though his outlet opened only three months ago. The most popular filling is BLT (bacon, lettuce and tomato) at pounds 1.39; but the specials, including tomato, mozzarella and avocado with Caesar dressing (pounds 1.95), and the de luxe sushi (pounds 4.95), are also favourites.

'What I have to do is to educate Croydon to bridge the gap, and realise that you can come into a place like this and have real, quality food, but still be able to get good value. Our cheapest sandwich is just 99p.'

'I set up less than two years ago,' says Juliet Shield at Hand to Mouth, which boasts Conran flower holders, solid beechwood stools and designer murals, 'and I was warned my ideas were too up-market for Liverpool. But if you have a good product, and show value for money, people will eventually come. You just have to sit it out.'

Now, people travel from as far away as Southport for her freshly-made chicken with lemon-mayonnaise sandwiches, Lake District bread and Whittard's leaf tea. All the food is cooked on site, in an open-plan kitchen behind the counter. The cheapest sandwich is egg and cress at pounds 1.10, the most expensive devilled crab with lime at pounds 1.95.

Martin Upton, proprietor of Philpotts in Birmingham, believes the secret is having perfect food, and showing it off. 'Here, the customer comes in, and has to walk past the till right down the length of the shop. They see all our soups, hot food, specials, and all the sandwich fillings. It makes them feel hungry.' He believes the flexibility of the sandwich is its greatest asset. 'If I owned a McDonald's store and wanted to change a certain ingredient, it would take about three years. But last night I invented a new sandwich - roast beef and jalapeno (chilli) with tomato and onion sauce - and it was in the shop today.'

Sadly, Mr Upton's jalapeno invention won't be up for the Most Innovative Sandwich Award, at next week's prize-giving ceremony at London's Royal Lancaster Hotel, against such wacky contenders as 'Jewel of the East' (Thai chicken) from Griffins in Sutton Coldfield, and 'The 24-Hour Clock', an extraordinary affair involving eggs, chicken, grapes and a whole loaf, from Clocks Sandwich Bar in Kingston.

'Interesting fillings and faultless quality,' pronounces Debbie Whitney, defining the perfect sandwich. Ms Whitney, who owns the fourth finalist, Chatwins, in Crewe, is delighted to achieve recognition after seven years running her bar. 'I only use cold-water prawns, breast of chicken, freshly-smoked ham, and so on.' Her prawn sandwich with Marie Rose sauce (pounds 1.55) once inspired a customer to ring her on his car phone to declare it the best he had ever tasted.

Now Debbie Whitney's renowned sandwiches have gone on sale at local petrol stations. 'I supply three local garages here. Everyone knows most garage sandwiches are appalling, and I think it's important to bump up the standard. I've begun to sell as many a day there as I do here in the shop.'

Each bar has been judged by one of a team of food experts, each of whom knows what to look for. 'I walked in; it was immaculate, the queue was quick, and you could see all the produce straight away,' says one judge, Steve Manning, about Philpotts.

'The range is way above all else in the North of England,' says another judge, Lawrence Gilbert, of the Hand to Mouth. 'There is a sense of orderliness in the shop and a sense of understanding about food. The business quarter recognises this; Juliet Shield sends out sandwiches that go on to business tables all over Liverpool. And the bread] It comes from hundreds of miles away. She is totally dedicated to achieving excellence.'

The award will be announced over a grand dinner (no sandwiches) on Wednesday night. The title will be very good for business. 'If I win,' says Raymond Simonds, 'I'll have it plastered up outside in half an hour.'

'I'm simply overwhelmed to be a finalist,' says Debbie Whitney. 'It's so good to be acknowledged; it makes you want to go on buttering the bread.'

(Photograph omitted)