After four weeks at the top, Asda has plummeted to third position in our weekly basket survey, losing out to Tesco and Morrisons. The multiple can blame its relegation partly on the end of its offer on red seedless grapes, which shot up in price from £1.98 to £2.98 - 1p more than Tesco's and Sainsbury's offerings. It also lost ground to Tesco on the price of its pork pies, which were 41p more expensive. Swapping places with Asda, last week's fourth-cheapest retailer, Tesco produced a winning basket, almost 50p cheaper than its rival's at £46.80. The multiple had made no major price cuts this week but offered low prices across the list. Morrisons, which came in third, offered the cheapest kiwifruit at 89p and pork pies that were 30p less than those at Tesco. Although its price freeze was clearly evident this week, the survey showed that the price of Lynx shower gel had risen by 88p. It also revealed that the gap between the cheapest four has narrowed significantly. Last week Sainsbury's had a basket total that was £3.52 more expensive than the cheapest retailer. This week the gap has been closed to just 69p. Sainsbury's £47.49 basket contained the cheapest Domestos bleach and red seedless grapes that were £1.01 per kg less than they were last week. Waitrose and Somerfield are still no nearer to the basket totals of the four cheapest retailers. Waitrose has clinched fifth place again this week but its red seedless grapes were £1 more than Somerfield's. It generally kept the price of its branded food in line with the cheaper stores, but its own-label frozen garlic baguettes were nearly twice the price of Asda's. Somerfield is once again the most expensive store in the survey with the most expensive prices for 20 items on the list. However, Somerfield has lowered the price of its frozen garlic baguettes by 17p. Last week Somerfield's pork pies were £2.29 - they were the second cheapest on the list this week at £1.14.