London's blue chips ended Thursday's session more than 100 points lower, as the European Central Bank (ECB) conference disappointed traders.The FTSE 100 closed 111.13 points below the opening bell, at 6,446.39.The ECB decided to keep key rates unchanged and unveiled further details of its asset-backed security (ABS) and covered bonds programmes that launch in mid-October.The central bank decided to maintain the interest rate on the main refinancing operations, the interest rates on the marginal lending facility and the deposit facility at 0.05%, 0.30% and -0.20% respectively.ABS and buying of covered bonds will last at least two years and will aim to address low inflation and weak economic growth in the euro-area. Asset purchases will start in the fourth quarter 2014, beginning with covered bonds in second-half of October.The monetary authority will buy debt of countries with ratings below BBB-, provided these countries are under a rescue programme, such as Cyprus and Greece."Together with the targeted longer-term refinancing operations, the purchase programmes will further enhance the transmission of monetary policy," the ECB explained in a statement.Capital Economics took Draghi's words as a strong hint that a deterioration in the inflation outlook in the coming months would result in the ECB "taking bolder, unconventional policy action", that would leave the door "wide open" for full-blown quantitative easing by the end of the year.Construction PMI hits eight-month high thanks to housebuildingThe UK construction sector activity has hit a new eight-month high, thanks to the housebuilding sector, according to Markit's purchasing managers' index (PMI) reading for September.Beating analyst expectations of a 63.5 reading, PMI climbed to 64.2, up 0.2 points from August. A reading above 50 signals growth.Markit attributed the upturn to house building, but noted that once again construction firms reported rapid growth of commercial activity and civil engineering, indicating an increased level of investment in office space, industrial units, retail space and infrastructure.Hargreaves rises after Numis upgradeHargreaves Lansdown was one of just a small handful of stocks to rise on Thursday, driven higher by Numis which upgraded its rating on the stock to 'buy'.Readacross from its US peer United Rentals sent shares in Ashtead into the red.Sainsbury continued its path lower following a disappointing update the previous session.Its rival, Morrison Supermarkets, unveiled plans for a price-match scheme where it will compare prices with discount chains Aldi and Lidl as well as its larger rivals.BAE Systems also fell after Investec downgraded the stock from 'hold' to 'sell' with a target price of 430p.Construction and facilities management group Carillion climbed after saying earnings and cash generation both remained in line with expectations for the full year after a robust third quarter.Domino's Pizza Group served up yet another tasty set of numbers, driven by a strong UK performance thanks to improved economic conditions, continued emphasis on meal deal promotions and more customers ordering online. For the 12 weeks ended 28 September, UK like-for-like (LFL) sales rose 12.9%, while system sales jumped 17.6% from £140.9m to £165.7m.Market MoverstechMARK 2,743.23 -1.62%FTSE 100 6,446.39 -1.69%FTSE 250 15,005.19 -1.35%FTSE 100 - RisersHargreaves Lansdown (HL.) 933.00p +0.43%Fresnillo (FRES) 749.50p +0.33%Randgold Resources Ltd. (RRS) 4,155.00p +0.02%FTSE 100 - FallersAshtead Group (AHT) 977.00p -4.59%Sainsbury (J) (SBRY) 224.80p -3.93%BG Group (BG.) 1,053.50p -3.61%Weir Group (WEIR) 2,343.00p -3.58%InterContinental Hotels Group (IHG) 2,251.00p -3.56%Mondi (MNDI) 976.50p -3.51%Babcock International Group (BAB) 1,047.00p -3.50%Tullow Oil (TLW) 609.50p -3.41%Pearson (PSON) 1,204.00p -2.98%Carnival (CCL) 2,343.00p -2.98%FTSE 250 - RisersAfrican Barrick Gold (ABG) 220.90p +5.64%Croda International (CRDA) 2,073.00p +4.17%Debenhams (DEB) 60.00p +3.81%Greencore Group (GNC) 236.00p +2.79%Alent (ALNT) 329.00p +2.49%SIG (SHI) 165.00p +2.42%Fidessa Group (FDSA) 2,281.00p +1.88%IP Group (IPO) 204.10p +1.80%Carillion (CLLN) 309.10p +1.58%3i Infrastructure (3IN) 141.70p +1.21%FTSE 250 - FallersKazakhmys (KAZ) 244.10p -6.15%Centamin (DI) (CEY) 57.90p -5.08%Hochschild Mining (HOC) 123.60p -5.07%Mitchells & Butlers (MAB) 349.00p -5.06%Domino Printing Sciences (DNO) 581.50p -4.83%Premier Oil (PMO) 309.80p -4.59%EnQuest (ENQ) 102.90p -4.55%Vedanta Resources (VED) 932.50p -4.31%Electrocomponents (ECM) 210.50p -4.23%Man Group (EMG) 113.30p -4.15%