Exclusive Tim Palmer Sainsbury is breaking new ground in the wine market with the introduction of a box containing two different wines. The Duo box is the brainchild of Patrick Darlington whose company developed the new-style packaging. Containing white and rosé wines from the Anjou region of France, it is being exclusively launched in the multiple this week. The boxed wine category has increased in value by 15% [ACNielsen] over the past year and Sainsbury said its sales are growing ahead of that. Boxed wine buyer Rachel Hibbert said: "Our good sales have been brought about by our focus on quality wines. "We have encouraged suppliers of bottled wines to put them in a box." Last year Sainsbury introduced Kumala, the South African brand from Western Wines, into the format with a Chardonnay at £14.99 and a Cabernet Sauvignon/Shiraz (£16.99). This year it followed it up with Pendulum, also from Western Wines. A rosé was introduced in the spring and a Chardonnay went on the shelves last month, both retailing at £14.99. Hibbert said: "The presence of exclusive top brands in the range has helped sales growth." The rosé and white wines were chosen for the Duo pack to capitalise on the summer drinks market. They offer a larger volume than a normal bottle (1.5 litres each) in an easy format. The main advantage is that the box is a convenient pack for the fridge, providing two chilled wines on tap for up to six weeks. Both wines were sourced from Sainsbury's current suppliers. The Duo retails at a competitive £12.99. Darlington is hoping that if sales go well the pack will be the forerunner of more twin offerings, probably two whites or two reds. {{DRINKS }}