Retailers hope for late Christmas rush However, retailers are predicting a wave of last minute spending this weekend. Today is forecast to be the busiest day of trading for supermarkets because Sunday trading laws mean customers will have just six hours to stock up for Christmas. J Sainsbury has hired 20,000 extra staff and brought 2,000 office workers to its stores to cope with Christmas demand. It is predicting that it will sell 250,000 bottles of champagne this weekend, 90,000 Norfolk Black and Bronze turkeys, 13m own-brand "pigs in blankets," and 52m brussels spouts. Because of the limited trading hours today, 35 Sainsbury's stores will open to midnight on Christmas Eve. Justin King, chief executive, said: "This weekend is our busiest time of year, so we're doing all we can to ensure our customers can get everything they need for a great Christmas." The London department store, Fortnum & Mason, experienced its three best days in sales terms last week, on Wed­nesday, Thursday and Friday. In-store sales were up 22pc on the same three days a year ago with online sales up 90pc.