Investors managed to take advantage of a quiet morning to push UK stocks higher on Wednesday following a sell-off the previous day.The FTSE 100 was up 0.57% at 6,988.37 by midday, with blue chips Imperial Tobacco and CRH leading the rise, along with a host of other construction and building materials stocks.The index had plunged 1.2% on Tuesday as a stronger dollar sent commodity prices tumbling - and subsequently mining and oil stocks - while concerns about uncertainty in Greece dampened sentiment.Spreadex analyst Connor Campbell said markets were holding off more losses "with painfully (or mercifully, depending on your view) little news to disrupt things as the day continued""Unlikely to bring with it too many unknowns, the Queen's Speech, nevertheless, could cause some movement on such a quiet Wednesday," he said.The Queen is set to put forward the agenda of the new government following the recent elections, with the focus on any comments about a UK referendum on EU membership following recent reports have suggested that David Cameron could fast-track plans for a vote to as early as next year.Consultancy EY warned on Wednesday that the uncertainty caused by the possibility of a referendum "will be disruptive and is a risk to the UK's foreign direct investment performance". Some 31% of those surveyed said their would either reduce or shelve planned investments up to 2017, EY said.Imperial and CRH riseImperial Tobacco gained after being given the green light by US trade regulators for its $4.7bn asset purchase from the merging Lorillard and Reynolds. The deal, which still must clear some smaller legal hurdles, is expected to complete within weeks.Shares in building materials group CRH rose strongly after finally entering into a binding offer with European cement giants Holcim and Lafarge to buy assets worth €6.5bn as part of their proposed merger.Others in the building and construction sectors were also in demand, including Ashtead, Travis Perkins, Wolseley and Persimmon.Royal Bank of Scotland fell amid speculation it could bid for part of Granite, which is a £13bn state-owned mortgage portfolio for sale by the UK government, according to Sky News.Synergy Health was a heavy faller, dropping nearly 17% on rumours that US regulators might block the takeover by Steris.Banknote printer De La Rue also plunged 9% after posting a steep decline in annual profits amid ongoing pricing pressures and giving a cautious outlook for the current year.Some of the fizz went out of Irn Bru maker AG Barr after sales fell 1.1% year-on-year in the first quarter.Insurers Beazley and Hiscox were both higher after JPMorgan Cazenove upgraded the stocks to 'overweight'. Meanwhile, engineer Weir Group was hit by a downgrade to 'hold' at Deutsche Bank.Market MoverstechMARK 3,306.05 +0.68%FTSE 100 6,988.37 +0.57%FTSE 250 18,177.54 +0.43%FTSE 100 - RisersCRH (CRH) 1,818.00p +2.36%Imperial Tobacco Group (IMT) 3,359.00p +2.28%easyJet (EZJ) 1,649.00p +2.04%SSE (SSE) 1,678.00p +2.01%Travis Perkins (TPK) 2,236.00p +2.01%Ashtead Group (AHT) 1,205.00p +1.77%G4S (GFS) 302.00p +1.58%Wolseley (WOS) 4,064.00p +1.55%Persimmon (PSN) 1,960.00p +1.55%Smiths Group (SMIN) 1,211.00p +1.51%FTSE 100 - FallersOld Mutual (OML) 227.00p -1.73%Weir Group (WEIR) 1,973.00p -1.45%Mondi (MNDI) 1,483.00p -1.27%Glencore (GLEN) 287.15p -0.90%Fresnillo (FRES) 730.00p -0.82%SABMiller (SAB) 3,530.50p -0.76%Coca-Cola HBC AG (CDI) (CCH) 1,449.00p -0.34%Randgold Resources Ltd. (RRS) 4,596.00p -0.33%Sainsbury (J) (SBRY) 255.60p -0.27%Standard Life (SL.) 492.70p -0.16%FTSE 250 - RisersBeazley (BEZ) 299.20p +5.69%RPS Group (RPS) 232.40p +3.47%Micro Focus International (MCRO) 1,333.00p +3.09%Electrocomponents (ECM) 242.40p +3.02%Hiscox Limited (CDI) (HSX) 856.50p +2.94%Cineworld Group (CINE) 518.00p +2.78%Interserve (IRV) 636.50p +2.74%Betfair Group (BET) 2,677.00p +2.21%Kaz Minerals (KAZ) 247.00p +2.19%Daejan Holdings (DJAN) 5,710.00p +2.15%FTSE 250 - FallersSynergy Health (SYR) 1,800.00p -16.82%De La Rue (DLAR) 505.00p -8.76%Brewin Dolphin Holdings (BRW) 324.20p -8.13%PZ Cussons (PZC) 358.60p -2.69%Ophir Energy (OPHR) 127.30p -2.60%Infinis Energy (INFI) 176.20p -2.54%Hunting (HTG) 585.00p -2.42%Investec (INVP) 609.00p -2.40%Telecom Plus (TEP) 815.50p -2.34%Premier Oil (PMO) 155.30p -2.27%