Europe's blue-chip shares take biggest one-day tumble since October

* Pan-European FTSEurofirst 300 index falls 1.9 percent

* Athens ATG index down 5.6 percent on political uncertainty

* Euro STOXX 50 down 3.1 pct, biggest one-day drop since Oct

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

By Atul Prakash

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

The euro zone's blue-chip Euro STOXX 50 fell 3.1 percent, the biggest one-day percentage drop since October, while the pan-European FTSEurofirst 300 index fell 1.9 percent to 1,336.94 points by 1535 GMT. Benchmark indexes in London, Frankfurt and Paris were down 1.5 to 2.6 percent.

Energy and mining stocks were the worst hit. The European oil and gas and basic resources indexes fell 3.8 percent and 3.1 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.

Political uncertainty in Greece rattled markets before elections later this month. The Athens ATG index fell 5.6 percent, with lenders National Bank (NYSE: NBHC - news) , Bank of Piraeus and Alpha Bank (Other OTC: ALBWF - news) down 5.2 to 7.4 percent.

"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.

"There is an increased risk that Greek stocks could slide even further."

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

Although most sectors in Europe were in negative territory following a broader market sell-off, expectations of cheaper oil and a weaker euro helped travel and leisure, down 0.3 percent, to outperform.

Carnival (LSE: CCL.L - news) , IAG and Air France-KLM (Other OTC: AFLYY - news) rose 1.7 to 2.1 percent, while Ryanair shares, up 1.5 percent, hit an all-time high after the company said December traffic grew 20 percent.

Danish television and sound system manufacturer Bang & Olufsen rose 4 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 manufacturer 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 from Madrid's alternative stock exchange in October to address questions raised by its auditor. Its shares were last down 64 percent. (Additional reporting by Lionel Laurent; Editing by Ruth Pitchford)