It was a volatile day for the UK equity market with stocks swinging between losses and gains for most of the session, with a late sell-off sending the FTSE 100 firmly in the red by the close.Service-sector activity data from across the globe largely came in below expectations with weak figures from the US in particular behind that steep declines seen by the end of the session.The FTSE 100 finished the day down 0.8% at 6,367, its worst close since 17 December when it settled at 6,336.48.Mining stocks had given the market a boost in the early afternoon by the news that top metals consumer China has fast-tracked $1trn of infrastructure projects in a bid to spur growth.However, data showing that growth in the US services sector slowed to a six-month low in December dampened sentiment by the close. The ISM non-manufacturing purchasing managers' index (PMI) fell from 59.3 to 56.2 last month, missing the forecast of 58.It was a similar story back home where the UK services PMI dropped from 58.6 in November to a 19-month low of 55.8. Meanwhile, the final reading of the Eurozone services PMI was unexpectedly revised lower from 51.7 to 51.4.Oil prices continued to be a worry for many, with the selling pressure on crude showing no signs of abating, adding to deflationary concerns for the global economy. West Texas oil fell 3.8% to $48.14 a barrel, while Brent slumped 2.9% to $51.59 a barrel.Miners rise, Ashtead and banks fallMining stocks rose strongly by the end of trade with Randgold, Fresnillo, Anglo American, Rio Tinto and Centamin among the best performers. Gold and silver miners were particularly in demand as precious metal prices gained.Heading the other way was equipment rental firm Ashtead on the back of negative readacross from US peer United Rentals which was hit with a broker downgrade on Monday night. Evercore lowered its rating for United Rentals from 'buy' to 'sell', saying that the recent collapse in oil will affect energy investments and the construction market.The heavyweight banking sector was mostly lower as continued concerns about Greek leaving the Eurozone hit financial shares such as RBS, Barclays, HSBC and Lloyds."Banking stocks are being battered for fears that the political uncertainty in Greece could turn into a region-wide financial crisis," said analyst David Madden from IG.Retailers were also weaker with Kingfisher, Ocado and Marks & Spencer finishing lower. Investors of Sports Direct and JD Sports Fashion meanwhile were reacting to the news that retail peer Bank Fashion has entered into administration.Market MoverstechMARK 2,911.36 -1.04%FTSE 100 6,366.51 -0.79%FTSE 250 15,778.65 -0.90%FTSE 100 - RisersRandgold Resources Ltd. (RRS) 4,757.00p +4.87%Fresnillo (FRES) 790.50p +2.86%Anglo American (AAL) 1,155.00p +2.53%Rio Tinto (RIO) 2,944.50p +2.12%Shire Plc (SHP) 4,542.00p +1.23%Imperial Tobacco Group (IMT) 2,834.00p +1.03%SSE (SSE) 1,600.00p +1.01%Royal Mail (RMG) 414.20p +0.98%Intertek Group (ITRK) 2,298.00p +0.97%BG Group (BG.) 848.50p +0.81%FTSE 100 - FallersAshtead Group (AHT) 1,109.00p -6.18%ARM Holdings (ARM) 943.50p -4.41%Kingfisher (KGF) 316.80p -3.44%Sports Direct International (SPD) 692.00p -3.01%Smiths Group (SMIN) 1,047.00p -2.79%Hargreaves Lansdown (HL.) 956.50p -2.79%Schroders (SDR) 2,563.00p -2.70%RSA Insurance Group (RSA) 419.90p -2.64%International Consolidated Airlines Group SA (CDI) (IAG) 480.80p -2.57%St James's Place (STJ) 768.00p -2.54%FTSE 250 - RisersCentamin (DI) (CEY) 64.80p +6.84%Renishaw (RSW) 2,059.00p +4.94%Lonmin (LMI) 174.80p +4.92%Acacia Mining (ACA) 270.70p +4.48%Mitchells & Butlers (MAB) 395.00p +4.41%Just Eat (JE.) 330.00p +3.19%Tate & Lyle (TATE) 614.00p +2.76%esure Group (ESUR) 211.20p +2.18%Debenhams (DEB) 77.15p +2.05%TSB Banking Group (TSB) 283.50p +1.80%FTSE 250 - FallersOcado Group (OCDO) 387.10p -7.83%JD Sports Fashion (JD.) 472.00p -6.90%SSP Group (SSPG) 272.50p -6.00%Ladbrokes (LAD) 102.50p -5.62%Oxford Instruments (OXIG) 1,140.00p -4.92%Euromoney Institutional Investor (ERM) 1,026.00p -4.11%Hays (HAS) 141.50p -4.00%Spectris (SXS) 1,997.00p -3.99%Ophir Energy (OPHR) 134.60p -3.58%Nostrum Oil & Gas (NOG) 436.60p -3.41%