Benchmark indices across Europe and the US were making gains of between 3-5% on Wednesday afternoon after a united move by central banks to ease conditions in the global financial system. The FTSE 100 in London finished over the 5,500 mark, a closing level it has not reached since 16 November.CENTRAL BANKS ACTNews that the People's Bank of China (PBOC) had lowered the legal reserve requirement for Chinese banks by 50 basis points sent equities soaring back into positive territory at midday. That marks the first cut since December 2008 and has probably been undertaken as a move to support the economy and possibly to shield it from the unexpected turmoil in advanced economies. These gains were given an extra boost after six central banks, including the Federal Reserve and the Bank of England, have announced that they will take co-ordinated action to ease strains in financial markets by making it cheaper for banks to buy dollars. Under today's arrangement the banks have agreed to lower the pricing on existing temporary US dollar liquidity swap arrangements by 50 basis points. "We view today's agreement an important show of international coordination and it should also alleviate fears of a breakdown in cooperation emphasized by the resurfacing of press speculation of currency wars," said Barclays Capital analysts Laurent Fransolet and Thomas Harjes."It may also signal more internationally coordinated action to support euro area sovereigns under market stress with the involvement of the International Monetary Fund," they said.BANKS, MINERS JUMP ON CENTRAL BANK MOVESBanks and miners, two sectors typically sensitive to the swings in global macro-economic developments, rocketed on the news and dominated the top risers list on the FTSE 100. The mining sector swung into the blue and kept on rising after the PBOC move which attempts to bolster growth in the world's second-largest economy. Antofagasta, Kazakhmys, Rio Tinto, Xstrata, Vedanta Resources and BHP Billiton finished strong with gains ranging from 6-9%. Allied Gold Mining and New World Resources were making strong gains on the FTSE 250. Copper, gold and silver prices were soaring higher after the central bank moves.Banking peers RBS, Lloyds and Barclays were around 7% higher.Sage Group, the accountancy software company, saw its share price leap after it announced that its revenues had come in ahead of the consensus forecast for the 12 months to the end of September. Oil giant Cairn Energy didn't join the party though and continued to fall after saying that it had to plug and abandon two wells in Greenland.Utilities National Grid and Severn Trent, seen as defensive stocks, bore the brunt of the 'risk-on' appetite to fall lower. Only five blue chip stocks finished the day in the red.BCFTSE 100 - RisersAntofagasta (ANTO) 1,184.00p +9.23%Royal Bank of Scotland Group (RBS) 20.99p +7.53%Lloyds Banking Group (LLOY) 24.82p +7.10%Barclays (BARC) 180.25p +6.66%Investec (INVP) 361.50p +6.61%Kazakhmys (KAZ) 925.00p +6.51%Xstrata (XTA) 1,017.00p +6.49%Vedanta Resources (VED) 1,062.00p +6.47%Rio Tinto (RIO) 3,339.00p +6.39%BHP Billiton (BLT) 1,949.00p +6.15%FTSE 100 - FallersNational Grid (NG.) 624.50p -2.57%Resolution Ltd. (RSL) 235.60p -2.04%Tate & Lyle (TATE) 672.50p -1.68%Capita Group (CPI) 630.00p -1.25%Cairn Energy (CNE) 272.30p -0.98%FTSE 250 - RisersAllied Gold Mining (ALD) 200.80p +17.08%Pace (PIC) 51.25p +13.54%Savills (SVS) 319.80p +12.01%Grainger (GRI) 109.80p +11.81%Premier Foods (PFD) 5.87p +11.29%Exillon Energy (EXI) 287.60p +9.10%Yule Catto & Co (YULC) 170.10p +8.34%New World Resources A Shares (NWR) 469.70p +8.23%Millennium & Copthorne Hotels (MLC) 430.00p +8.04%Elementis (ELM) 152.30p +7.78%FTSE 250 - FallersSDL (SDL) 609.00p -4.77%Kentz Corporation Ltd. (KENZ) 464.10p -3.31%Thomas Cook Group (TCG) 18.29p -3.23%Dairy Crest Group (DCG) 330.70p -2.53%Oxford Instruments (OXIG) 974.00p -2.50%De La Rue (DLAR) 908.00p -2.37%TalkTalk Telecom Group (TALK) 134.40p -1.90%EnQuest (ENQ) 99.50p -1.68%RIT Capital Partners (RCP) 1,240.00p -1.59%Halfords Group (HFD) 329.90p -1.26%