However, the FTSE 250 rallied 0.7 percent to its highest since early November thanks to gains in sterling as investors awaited the outcome of Brexit talks between Britain and the European Union. Trading remained muted with U.S. markets closed on account of Presidents Day. FTSE 100's volume was about 60 percent of its 90-day average and the midcaps stood at 76 percent of theirs.
Defensive stocks, which are deemed to be a safe bet at times of uncertainty, were among the big fallers. Healthcare and consumer stocks led the fall with Accendo Markets analyst Michael van Dulken pointing to some profit-taking. As a result, oil majors BP and Shell skidded despite higher crude prices, and AstraZeneca, British American Tobacco, GlaxoSmithKline also ended in the red.
"I guess many people have been looking with the FTSE in a rising channel and nudging the ceiling of the channel, 'let's crystallise some of those profits before they get pulled away either by a trouble with trade talks or a Brexit problem'," van Dulken said. Consumer goods giant Reckitt Benckiser was a ray of sunshine, rising 4.6 percent on its best day since late-July as its fourth-quarter sales growth topped estimates thanks to improvements in its health and home and hygiene businesses.
On the small cap index, retailer McColl's jumped 11.5 percent after saying it was on course for higher like-for-like sales in the first quarter and Petra Diamonds added 2.3 percent following CEO appointment. All but one sector closed in the positive territory on the midcap index.
A standout faller was online trading platform Plus500 that tumbled 12.8 percent after confirming late on Friday that it failed to disclose certain losses from customer trading due to a drafting error in its 2017 report. Plus500 lost nearly half its value last week after a profit warning and a Times newspaper report of the accounting lag.
AIM-listed Footasylum nearly doubled in market value and bagged its biggest intra-day gain on record after JD Sports bought an 8.3 percent stake and said it was prepared to increase its holding up to 29.9 percent. (Reporting by Muvija M and Shashwat Awasthi in Bengaluru, additional reporting by Helen Reid in London; Editing by Alison Williams)