LONDON (AFX) - John Lewis Partnership said department store sales in the week to Oct 13 were down 1.2 pct compared to last year, while sales at its Waitrose food retailing chain were up 6.3 pct. Total sales increased 2.5 pct. In the 11 week period to Oct 13 department store sales increased 6.8 pct versus last year, Waitrose sales were up 6.6 pct and total sales were also up 6.6 pct. John Lewis' estimate of department store sales for the half-year as a whole is for an increase of 9.4 pct on 2000-01, with Waitrose sales up 4.5 pct and total sales up 7.0 pct. The retailer said it was disappointed by the performance of its department stores in the week to Oct 13. It blamed the warm weather on Saturday for the shortfall. "There may be a temptation to put all this down to world events, but we should not underestimate the very significant impact of the weather," said Luke Mayhew director of trading. "The spring-like conditions were the major influence on the setback in fashi ons, menswear and childrenswear. Temperatures of over 20 degrees and customers getting out their summer clothes again hardly inspire shopping for winter fashion." Mayhew said it will be some weeks before the retailer can tell if underlying trading conditions have fundamentally changed. "However, there now looks a strong chance that the increase in sales as we head towards Christmas is likely to be even later than it has been in recent years."