(For a Reuters live blog on U.S., UK and European stock markets, click LIVE/ or type LIVE/ in a news window) * FTSE 100 down 0.1%, FTSE 250 adds 0.2% Feb 19 (Reuters) - The FTSE 100 was muted on Friday as a bigger-than-expected drop in January retail sales underscored the business damage from a prolonged nationwide lockdown, while NatWest group fell after swinging to an annual loss. The commodity-heavy FTSE 100 was down 0.1%, with BP and Royal Dutch Shell falling 1.3% and 1.1%, respectively. Data on Friday showed British retail sales tumbled much more than expected in January as non-essential shops went back into coronavirus lockdowns. Flash readings of business activity data, due at 0930 GMT, are likely to show the services sector struggling to return to growth in February. In company news, NatWest fell 0.1% after the company swung to a full-year loss for 2020 after COVID-19 lockdowns crunched household spending. UK real estate investment trust Segro Plc rose 0.3% after posting an 11% jump in annual profit for 2020. (Reporting by Shivani Kumaresan in Bengaluru; Editing by Vinay Dwivedi)