"The last few turbulent trading sessions have all but wiped out what had been a strong start to the year," said Richard Hunter, head of markets at Interactive Investor.
Progress on the coronavirus vaccine rollout helped sentiment but concerns over the emergence of new strains, said to be more infectious, made for caution.
Meanwhile in Europe's biggest economy Germany, exports tumbled 24 percent month-on-month in April to 75.7 billion euros ($85.5 billion), official data showed.