The FTSE 100 lost 45.67 points, or 0.7 per cent, to 6,672.37, extending its decline this week to 2.8 per cent. The broader FTSE All-Share Index also slid 0.7 per cent.
LSE had its biggest fall since April, after Qatar sold £260.1m of its shares, ending 3.07 per cent down on 1,896p.
The biggest faller was investment services outfit Hargreaves Lansdown, which dropped 4.75 per cent to 1,124p.
Barclays declined to its lowest level since November 2012, falling 3.03 per cent to 205.1p, while HSBC, Europe’s largest lender, dropped 1.3 per cent to 589p.
British Airways owner IAG and budget airline EasyJet followed their European peers lower, down 2.44 per cent and 1.17 per cent respectively.
On the up side, Burberry rose 3.2 per cent as first-quarter sales beat analyst estimates.