A window seat is a must when you fly into the pink city of Toulouse because of the astonishing bird's eye view of the natural horseshoe bends in the Lot river as it snakes westward. The flat pastureland and sleepy towns of the Lot Valley exude such an air of deep tranquillity that nothing appears to move. Yet for anyone lulled into a false sense of inertia, South-west France's wine region of Cahors is out to prove that nothing could be further from the truth.

Lot Valley malbec is so deep-coloured that in medieval times, the 'black wine of Cahors' became the backbone of puny Bordeaux. But the 19th-century phylloxera plague sealed the region's fate. When I first visited 20 years ago, there were a handful of respected names, Gaudou, Clos de Gamot and Clos Triguedina among them, but little else besides apart from a co-operative churning out plonk and a self-appointed bunch of grandees known as the Seigneurs de Cahors. I took my own wine there on holiday, no joking.

Visiting Château du Cèdre's Pascal Verhaeghe, I had little inkling then that he was to spearhead the Cahors revolution that has transformed its wines today. With Jean-Marie Sigaud and Lagrezette's Alain Perrin, Verhaeghe introduced a charter of quality in 1999. The aim was to focus on vineyards, mostly situated on the upper banks of the river, capable of producing the best wines. Working to increase the potential of the malbec grape's drinkability, they have inspired a new generation, names like Mathieu Cosse, Catherine Maisonnneuve, Germain Croisille, Mathieu Molinié and Daniel Fournier.

The winds of change blew the young Parisian entrepreneur Philippe Lejeune into Château Chambert, while the renowned vineyard guru Claude Bourguignon planted vines in its ancient soils. Young turks such as Emmanuel Rybinski of Clos Troteligotte, Julien Ilbert of Château Combel la Serre and Sébastien Dauliac of Domaine de Capelanel are set on maintaining the new high standards. At the same time, by cleverly capitalising on the malbec name after forming an alliance with malbec's New World home of Argentina, Cahors has added saleability to its new approachable style.

Wines such as the invitingly blackcurranty, vigorous yet succulent 2010 Château de Gaudou, £7.99, Majestic, and the 2010 Château Lafleur de Haute-Serre, £10.49, Waitrose, with its pepper-tinged fruit and savoury quality, show what good value Cahors can be. A rung up the ladder, the 2010 Château du Cèdre, £98/6, in bond, Bancroft Wines (020-7232 5440) is wonderfully aromatic, mulberryish and refined, the 2009 Domaine de la Bérangeraie, La Gorgée de Mathis Bacchus, £18.67, Vine Trail (0117 921 1770), a blend of black cherry, spiced plum and liquorice spice.