If you've noticed something bright, new and shiny winking at you from the Tesco wine department, then you've already met the supermarket's new fine wine range. Finer, if that's possible, than Tesco Finest (its superior own-label range at £4.99 to £18.99), 50 new wines have been selected to lie suggestively in a specially designed answer to the wine merchant's rack. So if Tesco, which sells one in every five take-home wines in the UK, has come under fire for its readiness to promote cheap wines and squeeze the pips out of the supplier, is this mere window-dressing or a genuine attempt to bring upmarket bottles to its shoppers?

Tesco says the extension to the existing 750-strong range is a response to customers looking for more expensive wines. This tallies with Majestic's recent finding that customers are trading up significantly and a report last year by the wine-trade exhibition organiser, Vinexpo, showing greater demand for higher-priced wines. Waitrose has already proved with its Inner Cellar that fine wines can work in a supermarket. Tesco's initiative dovetails with tesco.com, which offers armchair customers a chance to have one-off parcels delivered by the case, and Tesco Wine Club, aimed at attracting the more wine-steeped of its 535,000 Clubcard holders to its London and Manchester Wine Club fairs.

The new "mini instore wine merchants", which feature 50 new wines, ranging in price from £7.99 to £99.99, are set up in 90 stores throughout the UK, each store selected from Clubcard data for relative customer affluence. With eight wines at under a tenner and a further 30 at below £20, the prices suggest that the wines aren't intended to gather dust. There's a handful of icons, like the ethereal 1997 Bollinger Grande Année and Australia's acclaimed Penfolds 1999 Grange, but even at £54.99 and £99.99 respectively, the prices are not extortionate. And at £21.99, England's intensely flavoured, yeasty 1999 Nyetimber Classic Cuvée is on a par with the vintage at Waitrose.

With limited quantities of as few as 300 cases, many of the wines are exclusive and there are some genuine finds. In the under-£10 section, the 2004 Sancerre Les Tuileries, from Michel Redde, £9.99, is a typically herbal, leafy, dry Loire white with underlying minerality, the 2004 Domaine Thibert Macon Fuissé, £7.99, a ripe, subtly oaked classy white burgundy, while the Geoff Merrill 1998 Chardonnay, £8.99, offers the mature, butterscotchy flavours of a traditional Oz classic. And from Argentina, the 2003 Terrazas de los Andes Reserva Malbec, £9.99, is exceptionally rich and vibrant in blackberry fruit flavours.

In the under £20 section, there's a complex dry white burgundy in the 2004 Rully 1er cru Mont Palais Blanc, £13.99, from Jaeger-Defaix and an extraordinarily exotic, pot pourri-scented 2000 Gewürztraminer Herrenweg, Domaine Zind-Humbrecht, £16.99. The clarets and red burgundies are generally acceptable if nothing to write home about, with an approachably stylish red Bordeaux in the 2001 Château de Lussac St Emilion, £11.99, and from Italy an aromatic and hauntingly delicate 1999 Barolo Riserva Tortoniano, Michele Chiarlo, £19.99.

The general quality of the selection and the stated intention to keep turnover brisk are positive signs. The £1m investment in refurbishment, along with the wine team's involvement, suggests a genuine effort to raise standards rather than simply dress the shop window. If this signals a major shift from squeezing suppliers and helps raise the game at all levels of the wine range, then three cheers really would be in order.