(Close): A moderate fall for shares in London, with some analysts blaming worries over the situation in Iraq.
(Open): Shares in Barclays sank 5% after the New York attorney general filed a fraud lawsuit against the bank.
The benchmark FTSE 100 index closed 0.8% lower at 6,733.
The lawsuit alleges the bank falsified documents and misrepresented systems in place to protect certain investors from aggressive high-frequency trading.
"Fresh geopolitical concerns in Iraq may have given investors the perfect excuse to take profits off the table," said Desmond Chua at CMC Markets.
Barclays said it was taking the allegations "very seriously".
Meggitt, which makes parts for the aerospace industry, was the biggest loser on the index, falling 3.2% after JP Morgan downgraded the shares.
Despite the hit to Barclays shares, the FTSE 100 index was up 9.79 points at 6,743.41. Shares in the London Stock Exchange rose 4.4%.
JP Morgan said that Meggitt had shown little signs of recovery since warning about its performance at the end of last year.
On the currency markets, the pound was unchanged against the dollar at $1.6983 and was also flat against the euro at 1.2459 euros.
Drugs firm Shire was the biggest winner, closing 2.6% higher after a US court backed its patents on hyperactivity drug Vyvanse.
The decision prevents generic drug manufacturers from making low-price copies of the top-selling drug before 2023.
Some gloomy economic news from the US also weighed on the markets today.
The US economy suffered its worst performance for five years in the first quarter of 2014.
The economy shrank at an annualised rate of 2.9% in the first three months of the year, the third estimate from the US Commerce Department showed.
On the currency markets, the pound fell was flat against the dollar at $1.6981 and dropped two fifths of a euro cent against the euro to 1.2490 euros.
