The exporter-heavy FTSE 100 was down 0.6%, also pressured by the sterling which touched an eight-month high as the dollar fell in the aftermath of a speech by Federal Reserve Chairman Jerome Powell.
Historic global stimulus has helped UK equity markets in their fourth monthly increase in five, but the pace of gains has slowed as economic data points to a slower-than-expected recovery from a pandemic-induced slump.
"As markets have turned decidedly more risk-on, correction fears are mounting," Barclays analysts wrote in a note.
"A pullback is of course possible, but we remain of the view that the unwind of the massive flight to safety seen year-to-date is likely closer to the beginning than the end."
Bank of England Governor Andrew Bailey said the central bank has more ammunition to support the economy and that big, aggressive bond-buying pushes are most effective when crises strike.
Britain's mid-cap FTSE 250 rose 0.2%, with homebuilders <.FTNMX3720> leading gains.
Earlier, Japanese financial markets fell after news that Prime Minister Shinzo Abe will resign for health reasons.
"The surprise announcement made a lot of headlines, but it didn't have a huge impact on stocks in Europe," said David Madden, market analyst at CMC Markets UK.
"Things have been a little directionless today, partially because there has been a lack of local news, but it is likely that UK-based traders are winding down ahead of the long weekend."
Baker Greggs shed 1.6% as the report said its distribution centre had been temporarily closed for a deep clean after an undisclosed number of staff tested positive for COVID-19.
By Sagarika Jaisinghani and Shreyashi Sanyal