Europe's blue-chip shares take biggest one-day tumble in 3 years

* Euro STOXX 50 down 3.7 pct

* Pan-European FTSEurofirst 300 index ends 2.3 pct lower

* Athens ATG index down 5.6 percent on political uncertainty

* Multi-year lows for oil and copper hurt commodities stocks

By Atul Prakash

LONDON, Jan 5 (Reuters) - European equities fell sharply in choppy trading on Monday, with concerns over Greece's future in the euro zone and a steep drop in prices of crude oil and copper hurting financial and commodities stocks the most.

Energy and mining shares were the worst hit. The European oil and gas and basic resources indexes fell 4.9 percent and 3.6 percent respectively after a supply glut sent oil prices to a 5-1/2-year low and copper hit a 4-1/2-year trough due to a stronger dollar.

Investors fear the Jan. 25 election in Greece could vault the left-wing Syriza party into power, raising the risk of a sovereign default.

The euro zone's blue-chip Euro STOXX 50 fell 3.7 percent, the biggest one-day percentage drop since late 2011. Greece's ATG fell 5.6 percent, with National Bank (NYSE: NBHC - news) , Bank of Piraeus and Alpha Bank (Other OTC: ALBWF - news) slipping 5.2 to 7.4 percent.

"The rise of the anti-austerity Syriza party has sent shivers down the spine of dealers. A victory for the left-wing party does not automatically mean a Greek exit (from the euro zone) but traders will certainly see it that way," IG (LSE: IGG.L - news) analyst Alastair McCaig said.

Der Spiegel news magazine, citing unnamed government sources, reported on Saturday that the German government believes the currency bloc would now be able to cope with a Greece exit if that proved necessary.

Greek jitters hit regional stocks. Italy's FTSE MIB and Spain's IBEX fell 4.9 percent and 3.5 percent respectively, while Britain's FTSE, Germany's DAX and France's CAC 40 were down 2.0 to 3.3 percent. The pan-European FTSEurofirst 300 ended 2.3 percent weaker at 1,332.47 points.

"The logical thing to do right now is to avoid Greece. A lot of people are getting out of Greek assets thinking that probably it would be too late after the elections. Banking stocks are likely to bear the brunt of the sell-off," Ronny Claeys, senior strategist at KBC Asset Management, said.

Although most sectors in Europe were in negative territory following a broader market sell-off, the travel and leisure index, down 0.7 percent, outperformed on expectations that cheaper oil and a weaker euro would help the companies.

Carnival (LSE: CCL.L - news) , IAG and Air France-KLM (Other OTC: AFLYY - news) rose 1.3 to 2.1 percent, while Ryanair shares, up 1.3 percent, hit an all-time high after the company said December traffic grew 20 percent.

Many in the market have been hoping it will get support from the European Central Bank. Data showing German inflation slowing to its lowest in more than five years in December has strengthened arguments for the ECB to unveil unconventional measures later this month, despite the qualms of some of its policymakers, to ward off a deflationary spiral in the euro zone.

Among other movers, Danish television and sound system manufacturer Bang & Olufsen rose 3.6 percent after saying it would be prepared to look at any takeover approaches it received after lowering its profit guidance last month.

Spanish carbon fibre maker Carbures restarted trading down 74 percent after restating its 2014 first-half results on Friday and saying it expected to report a full-year loss. It had requested the suspension of its shares in October to address questions raised by its auditor. Its shares were last down 66 percent. (Additional reporting by Lionel Laurent; Editing by Ruth Pitchford)