Grim US data sparks shares slide

The 2.7% fall in December retail sales has sparked fresh fears about the state of the world's largest economy, analysts said. 

London's FTSE 100 index closed down by more than 5% in mid-afternoon trading, with banks among the biggest fallers. 

On Wall Street, the key indexes fell about 3%, while the main market in France and Germany lost about 4.5%