European stock markets were mixed on Wednesday as Prime Minister David Cameron announced plans for a potential referendum on Britain\'s EU future, and official data revealed a deepening of Spain\'s recession. In midday deals, London\'s FTSE 100 index of top companies edged up 0.08 percent to 6,179.15 points. Frankfurt\'s DAX 30 rose 0.19 percent to 7,711.42 points and in Paris the CAC 40 lost 0.32 percent to 3,729.69. Madrid\'s IBEX 35 fell by 0.27 percent in value to stand at 8,610.50 points. In foreign exchange trade, the European single currency rose to $1.3338 from $1.3321 late in New York on Tuesday. Sterling climbed versus the euro and dollar after upbeat British unemployment figures, dealers said. On the London Bullion Market, gold prices nudged higher to $1,692.25 an ounce from $1,690.50. \"Another eventful day but little or no reaction by European markets,\" said Ishaq Siddiqi, market strategist at ETX Capital trading group. \"Cameron pledged to renegotiate Britain\'s relationship with the EU by holding a referendum in 2017, if his party is elected again\" while \"after yesterday\'s strong Spanish debt auction, we have had some damp forecasts for Spanish economic growth in the fourth quarter.\" He added: \"European investors are currently holding back from building risk, in wait for more corporate earnings and US lawmakers kicking the can down the road by voting on a three-month extension on raising the debt ceiling.\" British Prime Minister David Cameron on Wednesday promised to hold a referendum by the end of 2017 if he wins the next general election, giving British people the choice of staying in or leaving the European Union. Cameron said he wants to first renegotiate the terms of Britain\'s membership because \"public disillusionment with the EU is at an all-time high.\" The British leader said the EU was grappling with the eurozone, \"a crisis of European competitiveness\" and the gap between the EU and its citizens had \"grown dramatically in recent years.\" He added: \"If we don\'t address these challenges, the danger is that Europe will fail and the British people will drift towards the exit.\" The Bank of Spain meanwhile said that Spain\'s economy took its steepest dive in more than three years in the final quarter of 2012 as high unemployment and biting austerity measures slashed demand. Available data pointed to gross domestic product plunging by 0.6 percent on a quarterly basis in the final three months of last year for the indebted eurozone country, after a 0.3-percent dip the previous quarter, it said. That marked the sharpest quarterly fall in Spanish economic output since the second quarter of 2009 when the eurozone\'s fourth biggest economy was reeling from a massive property crash. -- Unilever rises, Tui Travel slumps -- On the corporate front, shares in Unilever jumped 2.94 percent to 2,523 pence after the Anglo-Dutch food and cosmetics giant reported annual net profits up 5.0 percent to 4.48 billion euros ($5.96 billion). British-listed TUI Travel slumped 4.0 percent to 280.2 pence after German tourism giant TUI decided not to make a takeover offer for Europe\'s biggest tour operator, in which it already holds more than 50 percent. In Frankfurt, Siemens dropped 0.63 percent to 83.15 euros as the German engineering giant said earnings and orders fell in the first quarter, but it was hoping a shake-up of its businesses would enable it to meet full-year targets. BHP Billiton grew 1.15 percent to 2,105 pence after the global mining giant said its iron ore production in resource-rich Western Australia saw another record in the six months to December, while petroleum output was on track. After commodity price volatility in 2012, which prompted miners to shelve some expansions, BHP said iron ore production for the half year was 81.962 million tonnes, a 2.0-percent jump year-on-year. Asian stock markets mostly closed lower on Wednesday, in spite of a Wall Street rally, with Tokyo extending the previous day\'s fall as the yen strengthened following a Bank of Japan monetary policy shift, traders said. The Nikkei slumped 2.08 percent to 10,486.99 points after the central bank on Tuesday said it would fall into line with the new government and set a two-percent inflation target, while also launching an unlimited asset-buying scheme from next year. The bank also lifted its growth forecast, predicting gross domestic product would expand 2.3 percent in the year ended March 2014, up from an earlier 1.6 percent estimate.