The journey from Waterloo to Lille Europe takes only two hours and there are 10 trains a day in each direction, several of them stopping to pick up passengers at Ashford in Kent. Some detective work may be needed to find out about Eurostar's latest deals, as its sales staff seem strangely reluctant to talk about them, but what they should tell you is that the day return fare is currently pounds 49.50 each for a minimum of two people. After 14 December, the fare goes up to pounds 59 at weekends, and a prohibitive pounds 180 during the week.
Once you arrive in Lille, it would be possible to spend the whole day shopping and never be more than 50 yards from the station. Euralille, a large mall with more than a hundred shops, has been conveniently built between the Eurostar terminal and the domestic railway station; just follow the signs over the bridge to the city centre, and it is on the left. To concentrate your efforts here, though, would be to miss out on all those small specialist shops which French town centres do so well, so a better plan might be to continue into the city and save the mall - and its hypermarket - till later.
Once you reach the place de la Gare, go up the rue Faidherbe and you are on the edge of the old city and its pedestrianised streets. The squares here are geared up well for Christmas entertainment: a giant Ferris wheel has just gone up in the place du Theatre, with festive music playing in the background, and there is a merry-go-round in the place Rihour. Even those parts of the city that don't provide entertainment have some very classy decorations.
The rue de l'Hopital Militaire, which has several places to find unusual gifts, is a good place to start shopping. Vauban is a small bookshop that specialises in science fiction and cartoons - with the emphasis on Wallace and Gromit, and Tintin - as well as models and other related merchandise. Across the road is a second-hand bookshop; and the nearby Royez Musik has everything for the aspiring musician, and enough musical instruments to equip a symphony orchestra.
There are instruments of a less classical kind in the rue Esquermoise. At number 42, Artisans du Monde has a selection of drums and other percussion from around the world, as well as carved boxes, pictures and all manner of gifts. It also stocks some unusual Christmas cards - a nativity scene outlined in bamboo from Rwanda and colourful wool embroideries from Chile. Prices start at Fr10 for one card.
Opposite Artisans du Monde is Les Vins Gourmands, a well stocked wine shop with an extensive collection of wines from all over France. The staff are happy to pack your selection into cartons for you, to make the journey home easier and, if you're lucky, they'll probably have a few bottles open for tasting.
If you feel more like a cup of tea, go down to Meert; the fin-de-siecle- style tea-shop is a relaxing place to stop for a break, and it has delicious home-made cakes and chocolates to eat in or take away. Make your own choice of chocolates from the trays on the counter.
From here, head down the rue du Cure St Etienne to Philippe Olivier's cheese shop: you will be drawn inside by the smell of ripe cheeses, and the sheer variety on offer. If you want something local, go for Maroilles, Chaource or Boulette d'Avesnes. Around the next corner to the right is Gala Flowers, whose exotic displays may be hidden inside if the weather is very cold, the Genevieve Lethu cookshop, and a toy shop called Arts Populaires.
By this time you may be in need of lunch. The locals take their midday meal very seriously indeed and the best places tend to get booked up, so don't leave it too late before deciding to eat. A favourite place is the Brasserie des Moules, in the rue de Bethune. As its name suggests it specialises in mussels - which come served in large, steaming pans - but it also has a selection of other dishes, and the prices are reasonable: a goats' cheese salad, gigot d'agneau with gratin dauphinois, a dessert and a bottle of beaujolais nouveau costs about pounds 15.
After this, it might be time to consider going back to Euralille. A good choice is Nature et Decouvertes, where the stock is so varied that it would be possible to find a present for anyone on your list. Everything is based on "nature" in its broadest sense: unusual seeds, scented candles and outdoor lights, T-shirts, microscopes for adults and children, and lots of puzzles, books and games. The only disappointment is that some of the children's activities have lengthy instructions printed only in French, but most things are suitable for even the most monolingual recipient.
Another place worth looking inside is Loisirs et Creation, next to Euralille's main entrance. This shop has a large selection of Christmas decorations and the materials needed to make your own - artists' equipment and kits to make anything from sweets to embroidered pictures. Redoute, the long- established mail-order company, has some attractive scarves, hats and hair decorations, and Kitchenette has some bargain white porcelain - serving plates, dishes, and little pots that could be filled with sweets or nuts.
The best food shop in the mall is Paul's bakery. Apart from the branch here, there are also a couple in town, and it is a good place to stock up on a few treats for Christmas breakfast. It has a much larger selection than most bakeries: not just croissants, but a whole variety of other patisserie, including a stick with chocolate chips in it, called a pepite de chocolat. The prices are often reduced at the end of the day and it has lots of different breads, too, flavoured with cheese, onion or bacon, or made with different kinds of flour. Take some home for the freezer before nipping into the Carrefour hypermarket.
You will need Fr10 for the trolley, and plenty of time for the check- out, which doesn't have the capacity to cope with the size of the shop. Ready to seduce passing shoppers stand boxes of oysters packed and ready to go for Fr29.90 a kilo; baskets of dried and marzipan fruits from Fr40; a huge display of boxed chocolates; gift packs of five small jars of Bonne Maman jams for Fr12.30, and rows of drink, including the remaining stocks of France '98 champagne at Fr99 a bottle.
Which leaves you with the problem of how to get everything back to the train. The most convenient exit is opposite Paul's bakery; from there a path takes you straight into the station. But it does involve some steps, so there is no point in thinking that you can wheel your trolley on to the platform. If you really can't carry all your shopping, the best solution is to go back to the main entrance and look for a taxi.
There is now only one obstacle between you and a relaxing journey home. Eurostar allows passengers only three pieces of luggage, and it claims to reinforce this rule rigorously. As with a plane, the luggage is dealt with at check-in. Unfortunately, unlike a plane, the train doesn't have a hold where it can be stored; it just has an excess baggage charge of pounds 15 for each extra item. When I asked whether that might occasionally be waived, I was told it might not. But perhaps I had found the only person who isn't yet full of the Christmas spirit.
For the current two for one offer on day trips to Lille with Eurostar, phone 0990 186186. The deal is pounds 99 for two people on any day of the week until 14 December.
Brasserie des Moules, 34 rue de Bethune: 00 33 3 20 57 12 46
While in Lille don't miss the Goya exhibition. From 12 December to 14 March 1999, `Goya: un regard libre' is at the Palais des Beaux Arts, Place de la Republique, Lille (00 333 2006 7800). Entrance: Ff46