Sainsbury has reaffirmed its commitment to using warehouses as well as stores to source orders for the Sainsbury's to You home shopping service. The commercial viability of the warehouse picking model has been questioned following Asda's decision to close its picking centres and source all online orders from stores. Sainsbury assistant md Sara Weller insisted a mixed fulfilment model remained the most cost efficient for Sainsbury's to You, which sources orders from picking centres in London and Manchester and stores in all the major conurbations. Picking from stores in London was not viable, especially as volumes picked up, she added. "We want to stay flexible and have a mixture of solutions. A lot of our stores in London are too busy and too small to fulfil online orders." Since relaunch in September, volumes going through both warehouses had increased dramatically, she said. Coverage has reached 70%. Sainsbury chief executive Sir Peter Davis said it was "no secret" there had been some teething problems at the Park Royal picking centre in London, while Sainsbury began on the wrong tack by "slavishly following the American [warehouse picking] model". {{NEWS }}