UK stocks traded broadly sideways on Thursday morning with 'fiscal cliff' uncertainty dashing hopes that a deal between US politicians can be struck before Christmas.Trade was cautious in London this morning with just 14 points separating the Footsie's intraday low and high.Stocks finished slightly higher on Wednesday after Standard & Poor's upgraded Greece's credit rating to 'B-minus' and the IFO German business climate index beat expectations. However, gains were pared by the close after the White House Communications Director Dan Pfeiffer said that President Barack Obama would veto any 'plan B' from House Speaker John Boehner. "These frictions in Washington dashed hopes built earlier this week on talks of a compromise between both parties and the fact that negotiations stepped-up a gear," said market strategist Ishaq Siddiqi from ETX Capital."It now looks less likely that we will have a deal to avert the crisis just before the deadline at the end of this month - as such, investors are taking no chances before the last full trading week of the year ends and booking some profits on relatively overbought European indices," he said.FTSE 100: Weir in demand after acquisitionEngineering solutions group Weir rose after announcing that it is to buy pressure control rental equipment firm Mathena for £148m as it attempts to up its exposure to the fast-growing shale oil and gas market.Investec this morning raised its target price for the stock from 2,020p to 2,100p and reiterated its 'buy' rating, saying that the purchase "fits in nicely with Seaboard and diversifies Oil & Gas revenues away from the pressure pumping market".Outsourcing giant Serco gained after saying that it is on track to meet expectations for 2012 as it announced the sale of two operations at a loss. The firm said it expected to deliver a year of strong total revenue growth, including good organic growth.Distribution and outsourcing firm Bunzl extended losses following yesterday's pre-close trading update. JP Morgan Cazenove and UBS both cut their target prices for the stock this morning.Defence and aerospace group BAE Systems rebounded this morning following yesterday's admission that it is struggling to agree on a price for the supply of 72 Typhoon aircraft with Saudi Arabia. The company said that if it cannot come to an agreement, it would reduce its full-year underlying earnings per share by around three pence per share.FTSE 250: Lancashire and Amlin in the redInsurance outfit Lancashire Holdings fell after estimating the impact Hurricane Sandy on the business will be in the region of $40-60m. Sector peer Amlin put its losses from the US superstorm at £145m, most of which comes from reinsurance claims.Construction firm Balfour Beatty gained after saying its half-owned Hong Kong builder, Gammon Construction, had won a contract worth £270m.Transport group Go-Ahead was flat after saying that it has compensated London Midland customers with £7m of benefits after they were disrupted by cancellations and delays last year.FTSE 100 - RisersWeir Group (WEIR) 1,883.00p +3.92%Aggreko (AGK) 1,759.00p +3.47%InterContinental Hotels Group (IHG) 1,696.00p +2.23%Aberdeen Asset Management (ADN) 365.00p +1.84%GKN (GKN) 231.10p +1.76%BAE Systems (BA.) 347.20p +1.55%British American Tobacco (BATS) 3,131.00p +1.16%CRH (CRH) 1,238.00p +1.14%Intertek Group (ITRK) 3,163.00p +1.12%ARM Holdings (ARM) 783.50p +1.10%FTSE 100 - FallersUnited Utilities Group (UU.) 676.00p -1.74%Bunzl (BNZL) 1,007.00p -1.27%Reckitt Benckiser Group (RB.) 3,917.00p -1.21%BG Group (BG.) 1,012.00p -1.08%Melrose Industries (MRO) 231.60p -1.07%Polymetal International (POLY) 1,168.00p -1.02%Fresnillo (FRES) 1,893.00p -0.94%Rexam (REX) 441.00p -0.90%Burberry Group (BRBY) 1,238.00p -0.88%Smith & Nephew (SN.) 679.50p -0.88%FTSE 250 - RisersVesuvius (VSVS) 338.50p +4.48%Perform Group (PER) 383.40p +3.62%Man Group (EMG) 86.10p +3.11%Ocado Group (OCDO) 82.00p +2.56%Petra Diamonds Ltd.(DI) (PDL) 109.50p +2.34%William Hill (WMH) 358.50p +2.28%Investec (INVP) 423.70p +2.07%Talvivaara Mining Company (TALV) 103.30p +1.97%TUI Travel (TT.) 291.90p +1.88%Bumi (BUMI) 273.50p +1.82%FTSE 250 - FallersTelecity Group (TCY) 777.50p -2.81%Rank Group (RNK) 144.10p -2.64%Ferrexpo (FXPO) 251.50p -2.48%Heritage Oil (HOIL) 183.90p -2.28%Chemring Group (CHG) 236.60p -2.23%Computacenter (CCC) 413.50p -2.11%Imagination Technologies Group (IMG) 406.30p -2.10%Savills (SVS) 445.30p -1.94%African Barrick Gold (ABG) 434.40p -1.81%Bank of Georgia Holdings (BGEO) 1,013.00p -1.75%BC