(Reuters) -British meat producer Cranswick forecast annual profit ahead of its previous expectation on Thursday, helped by stronger-than-expected trading in the Christmas quarter. Trading updates from UK retailers and industry data have shown that shoppers prioritised spending on food rather than on discretionary general merchandise during Christmas, highlighting continued tight economic conditions in Britain. Cranswick, which produces fresh pork, bacon, gourmet sausages, poultry items and continental foods, said its third-quarter revenue growth was underpinned by higher volumes across all fou…