LONDON, Jan 13 (Reuters) - British retailer Marks & Spencer on Thursday nudged up its profit outlook after it reported a strong Christmas performance, particularly in food, where it outperformed the market.

M&S, Britain's most famous stores group which is recovering from a decade of decline, said it now expected full-year profit before tax and adjusted items to be at least 500 million pounds ($686 million) compared to previous guidance of about 500 million pounds.

It said food sales increased 12.4% against its pre-pandemic performance two years ago in the 13 weeks to Jan. 1. Clothing and home sales rose 3.2% on the same basis.

($1 = 0.7293 pounds) (Reporting by Paul Sandle; Editing by Kate Holton)