By Shawn Langlois, MarketWatch LONDON (MarketWatch) -- U.K. stocks dipped on Tuesday, extending the prior session's sharp drop, amid freshened concerns over what a Greece exit from the euro zone could mean for the markets. The FTSE 100 fell 0.4% to 5,446 in afternoon trade. The index shed 2% Monday after last-ditch attempts to form a coalition government in Greece stumbled over the weekend. That sparked another batch of fears that the country won't be able to push through with austerity reforms it promised in exchange for a bailout agreed in March. "This latest Hellenic national anti-incumbent swing," according to Barclays Capital analyst Edmund Shing, "has returned euro land to a state of political flux over continued efforts to reduce burgeoning public debt burdens, and has revived the existential question of the euro's continued existence, at least in its present form." Leading advancers in the FTSE, shares of security firm G4S PLC rose 3%, while Carnival PLC (CUK) bucked the trend by adding more than 2%. The biggest loser in the group were International Consolidated Airlines Group , down 5.1%. J.P. Morgan cut its rating on IAG to neutral from overweight, saying that the recent rally in the share price has made its peers, like top pick Lufthansa, more attractive. Experian PLC also took a hit, losing 2%. On the banking front, which is particularly susceptible to tensions in the euro zone, Barclays PLC (BCS) shares failed to find their footing, dropping another 3% on top of the prior session's notable retreat. Elsewhere, Rebekah Brooks, the former boss of News Corp.'s British newspaper unit News International, will be charged with conspiring to obstruct justice, prosecutors said Tuesday. Her husband, Charles Brooks, along with her former assistant, her chauffeur and two security men also faces charges, according to the Wall Street Journal. News Corp. (NWSA) owns the Wall Street Journal and MarketWatch, the publisher of this report. Of U.K. newspaper rivals, Trinity Mirror climbed 7%, while Daily Mail & General Trust was flat.