The blue-chip FTSE 100 was down 1.2%, snapping a five-day winning streak and wiping out most of the gains it made this month on hopes that an easing in restrictions would revive business activity.
The mid-cap FTSE 250 also shed 1.2%, with travel stocks plummeting again after a warning from European travel company TUI about thousands of job cuts to ride out a virtual halt in global travel.
In the latest sign of the corporate hit from the COVID-19 pandemic, Aston Martin slumped 7.8% to the bottom of the FTSE 250 after posting a first-quarter pretax loss as sales dropped by nearly a third.
Oil and gas producer Premier Oil fell 3.6% as it said it expected to be free cash flow neutral this year following a crash in oil prices. But Stock Spirits jumped 10.1% after posting a jump in first-half earnings as consumers stocked up on liquor ahead of tax hikes in its biggest markets, Poland and Czech Republic.