LONDON: Britain's blue-chip share index gave up earlier gains and slipped into negative territory on Monday in see-saw trade as lower oil prices pressured energy stocks and gambling companies were knocked by a report of a UK crackdown on offshore taxes.
A weaker opening on Wall Street and renewed worries about Italy also dented sentiment in afternoon trade, offsetting positive earnings from NMC Health Plc.
The FTSE 100 closed down 0.10 percent, as energy stocks knocked more than 12 points off the index. Oil services company Wood Group fell 2.8 percent, the second-largest loser, and BP Plc ended down 1.2 percent.
European shares tumbled 0.3 percent as a rally in Italian banks due to easing worries about the country's budget ran out of steam later in the session.
In the UK, gambling companies were under pressure after the Financial Times reported that Chancellor Philip Hammond was set to increase taxes paid by offshore gambling companies in his budget later this month.
Paddy Power Betfair dropped to the bottom of the index, down 4 percent and GVC Holdings fell 2.3 percent.
Positive earnings helped lift NMC Health to the top of the UK leader board, rising more than 5 percent for the biggest one-day gain since August last year.
The United Arab Emirates-based healthcare provider raised its full-year earnings and revenue forecasts, citing strong organic growth, and said it remained confident of achieving its longer-term margin guidance.
"This is likely to be welcomed by investors after a sticky spell for the shares, largely relating to wider market weakness," said Russ Mould, investment director at AJ Bell.
"The forecasts given today are impressive both in what they reveal about the growth trajectory and for their clarity."
The "impressive" performance by the UAE's largest private healthcare company contrasts with the difficulties faced by rival Mediclinic, which has struggled with the more mature Swiss market, he said.
UK mining companies were boosted by higher copper prices, with Anglo American Plc up 1.6 percent, amid hopes of stronger demand from China, the world's top commodities market, even as concerns grow about the impact of Washington's trade dispute with its top trading partner.
"The feel-good factor out of China at the moment has lifted the metals market," said David Madden, market analyst at CMC Markets UK.
Still the gains could be short-lived as the U.S.-China relationship comes under renewed pressure after U.S. Secretary of State Mike Pompeo's warning against investing in China.
Financials provided some support, with Lloyds Banking Group gaining 0.5 percent after the FT reported that the bank is planning to double its share buyback programme to almost £2 billion ($2.6 billion) next year.
The move was seen as a sign of the lender's confidence even as the economic outlook remains uncertain.
Outside of the blue-chips, broker moves and M&A activity were in focus on the mid-cap FTSE 250, which fell by 0.2 percent.
The top-ranked analyst at UBS upgraded Man Group to "buy", saying current pricing were an attractive entry point and pushing prices up 3.7 percent.
B&M European Value Retail SA was the third biggest gainer, up 4.3 percent on news of plans to buy France's Babou Stores Group.
Among the losers, Cairn Energy fell 6.6 percent with a Jefferies downgrade adding to pressure from lower oil prices.
Provident Financial dropped 1.65 percent as Barclays cut its price target after the sub-prime lender's trading update on Friday.