* Greek lawmakers fail to elect new president
* Athens' ATG equity index slumps, hitting European markets
* Spanish and Italian markets also slide
* UK's FTSE outperforms, helped by rise in gold miners
By Francesco Canepa
LONDON, Dec 29 (Reuters) - Greek stocks slumped on Monday, knocking European peers, after lawmakers rejected the government's candidate for president, leaving Greece facing a snap election that could derail its bailout programme.
Sole candidate Stavros Dimas, a former European Commissioner, fell short of the 180 vote supermajority needed to become president. He secured 168 votes in parliament, the same score he achieved in the second round.
Under Greek law, a general election must now be called, which polls suggest may be won by the left-wing Syriza party that has expressed opposition to Greece's bailout programme.
The vote sent the benchmark ATG Athex General Composite Share Price Index down by 8.6 percent, leaving it at levels not seen since 2012. The Athens index had already slumped due to fears that Dimas would fall short, dropping 12.8 percent on Dec. 9, and is down 33 percent in 2014.
IG market analyst Alastair McCaig said the Greek result could affect the European Central Bank's plans for new economic stimulus measures to tackle the economic weakness afflicting Europe, such as quantitative easing.
"Although this is a specific issue for Greece, it will raise fresh fears over the fate of the euro zone and the timelines for the possible implementation of a European version of QE.
"2015 could see an escalation in the debate over austerity, with the same old north-south divide on what is proportional still raging," McCaig said.
Greek banks bore the brunt of the hit to the Athens market, with Bank of Piraeus dropping 16.7 percent to record lows while National Bank of Greece fell 14.2 percent.
The Greek result also hit stock markets in Spain and Italy. Both southern European nations were also hit hard by the euro zone economic slump and sovereign debt crisis which led to Greece's 2010 bailout.
Spanish and Italian bond yields rose, pushing Madrid's IBEX down 1.4 percent while Milan's FTSE MIB fell 2.1 percent.
The euro zone's blue-chip Euro STOXX 50 index fell 0.4 percent but a 0.3 percent rise in Britain's FTSE 100 index helped to stabilise the pan-European FTSEurofirst 300 index.
The FTSE was helped by a rise in gold miners such as Fresnillo and Randgold, which were propped up as the price of gold moved higher.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Additional reporting by George Georgiopoulos in Athens; Editing by Catherine Evans)