The FTSE 100 index ended the Valentine's Day trading session 0.6% lower, down 0.8% for the week, while the midcap bourse rose 0.5% as it drew strength from the pound.

Global markets are expecting stimulus from central banks as new coronavirus showed no signs of peaking. U.S. Federal Reserve Chair Jerome Powell had last week warned that the economic impact from the outbreak could spill over globally.

The FTSE 100, with its larger exposure to commodity prices, has lagged its European counterpart, which has hovered at record high levels for most of the week, as investors shrugged off fears over the new virus.

London's main index has also been derailed as commodity prices take a hit from slower demand from China post the health crisis.

Among corporate news, AstraZeneca dropped over 4.3% as its quarterly earnings failed to match up to market expectations.

"Corporate updates triggered the declines in the pharma sector as well as the banking industry. Dealers are still worried about the health emergency in China as the situation isn't showing any signs of improving," CMC Markets analyst David Madden, said.

Royal Bank of Scotland fell 6.8%, ending the day at the bottom of the bluechip index, after its new top boss set out a new strategy that included cutting back the size of its loss-making investment bank and renaming the company NatWest.

"Every rose has its thorn; scratch beneath every RBS quarterly update and you'll find a sting or two," Markets.com analyst Neil Wilson wrote in note.

Warehousing specialist Segro outperformed the index, rising 1.5% and hitting a fresh high after it reported a jump in full-year profit and increased its dividend.

Among smaller stocks, biotechnology company Novacyt jumped 29% after it said it would launch a certified test for the new coronavirus next week.

Mosman Oil and Gas tanked 36% after it announced capital raise and updated the markets on its corporate strategy, which included the sale of some of its projects.

By Muvija M and Shashwat Awasthi