London shares ended Tuesday’s session in the red as jitters about the Scottish independence referendum offset more positive economic news.The FTSE 100 Index closed 5.77 points down at 6,829 as investors chewed over one poll giving Scottish separatists the lead and another with the ‘no’ campaign ahead by just one point.The nerves sent the pound tumbling against major currencies and wiped millions of pounds off companies with their headquarters or major operations in Scotland.Capital Spreads dealer William Nicholls said: “The Scottish independence debate continues to look as though it will be much harder to call than was ever expected.”Mixed economic news failed to stop the pound falling, with the UK trade deficit for July coming in worse-than-expected but industrial output lifting 0.5% in July after a 0.3% increase in June – its biggest rise in six months.Bank of England governor Mark Carney also tried to talk up the mood by telling trade unions that wages should start rising in real terms around the middle of next year.In corporate news, Scottish power & gas supplier SSE dimmed 21p to 1456p amid the volatility, but Lloyds Banking Group, which has its registered office in Scotland, rose 1.05p to 73.25p. Royal Bank of Scotland gained 1.7p to 344.2p and Standard Life increased 1.8p to 408.2p. But Aberdeen Asset Management backtracked 3.1p to 437.9p.Investors built up stakes in house-builders after positive comment from market analysts including Peel Hunt, which pointed to a realisation among the UK’s political parties that the housing shortage was a major problem.Persimmon led the Footsie risers higher with a 47p surge to 1358p while Barratt Developments climbed 6.3p to 367.1p. Builder’s merchant Wolseley also cashed in on the positive sentiment, rising 47p to 3294p.Investors tucked into supermarkets after figures showed August had the best monthly rise in high street retail sales since January, although slower than a year ago.Marks & Spencer jumped 5.7p to 433.8p, Sainsbury advanced 1.7p to 293.3p, Next put on 25p to 7145p and Tesco added 0.25p at 233.15p. Morrisons progressed 5.3p to 175.3p after Citigroup upgraded its rating on the stock to 'buy', saying the retailer’s 7.5% dividend yield was "safe".Oil and gas stocks faced pressure due to declining energy prices, with Brent oil prices hitting a 14-month low on Monday. Royal Dutch Shell leaked 36p to 2504.5p. Miners also had a bad day on concerns over weaker Chinese demand with iron ore prices hitting five year lows.BHP Billiton was the sector’s top faller with a 19p loss to 1872p and Glencore shed 2.8p to 366p.techMARK 2,866.07 +0.40%FTSE 100 6,829.00 -0.08%FTSE 250 15,786.87 +0.12%FTSE 100 - RisersPersimmon (PSN) 1,358.00p +3.58%Morrison (Wm) Supermarkets (MRW) 175.30p +3.12%Shire Plc (SHP) 5,240.00p +2.04%Meggitt (MGGT) 480.50p +2.02%Barratt Developments (BDEV) 367.10p +1.75%SABMiller (SAB) 3,479.00p +1.56%Wolseley (WOS) 3,294.00p +1.45%Lloyds Banking Group (LLOY) 73.25p +1.45%Smiths Group (SMIN) 1,358.00p +1.34%Marks & Spencer Group (MKS) 433.80p +1.33%FTSE 100 - FallersCoca-Cola HBC AG (CDI) (CCH) 1,395.00p -2.38%Associated British Foods (ABF) 2,700.00p -2.07%Royal Dutch Shell 'B' (RDSB) 2,504.50p -1.42%SSE (SSE) 1,456.00p -1.42%Capita (CPI) 1,176.00p -1.34%British Land Co (BLND) 719.00p -1.24%Anglo American (AAL) 1,527.00p -1.07%BHP Billiton (BLT) 1,872.00p -1.00%Royal Dutch Shell 'A' (RDSA) 2,412.50p -0.98%Prudential (PRU) 1,426.00p -0.97%FTSE 250 - RisersPetra Diamonds Ltd.(DI) (PDL) 192.10p +8.65%Crest Nicholson Holdings (CRST) 344.60p +3.48%Inmarsat (ISAT) 727.00p +3.12%Oxford Instruments (OXIG) 1,178.00p +3.06%Fenner (FENR) 360.00p +2.86%Greencore Group (GNC) 276.70p +2.48%Galliford Try (GFRD) 1,259.00p +2.36%Hunting (HTG) 885.00p +2.31%Genus (GNS) 1,115.00p +2.29%Jardine Lloyd Thompson Group (JLT) 1,007.00p +2.13%FTSE 250 - FallersAO World (AO.) 198.90p -4.83%Paragon Group Of Companies (PAG) 340.00p -3.41%Entertainment One Limited (ETO) 331.70p -3.07%Hays (HAS) 128.00p -2.59%Ted Baker (TED) 1,774.00p -2.58%AL Noor Hospitals Group (ANH) 1,082.00p -2.52%Centamin (DI) (CEY) 64.70p -2.34%Howden Joinery Group (HWDN) 348.00p -1.83%DCC (DCC) 3,485.00p -1.75%Rightmove (RMV) 2,360.00p -1.75%FTSE TechMARK - RisersPhoenix IT Group (PNX) 115.75p +10.50%Oxford Biomedica (OXB) 3.80p +4.83%Promethean World (PRW) 32.00p +4.07%NCC Group (NCC) 208.50p +2.33%E2V Technologies (E2V) 160.25p +2.23%Torotrak (TRK) 17.88p +2.14%RM (RM.) 134.00p +1.13%Innovation Group (TIG) 30.50p +0.83%Skyepharma (SKP) 306.75p +0.74%Dialight (DIA) 902.50p +0.06%FTSE TechMARK - FallersTriad Group (TRD) 13.25p -3.64%Anite (AIE) 89.00p -2.73%Optos (OPTS) 205.25p -1.79%Kofax Limited (DI) (KFX) 475.50p -1.71%Ricardo (RCDO) 623.00p -1.11%KCOM Group (KCOM) 97.50p -0.76%SDL (SDL) 315.00p -0.63%Vectura Group (VEC) 133.25p -0.56%IShares Euro Gov Bond 7-10YR UCITS ETF (IEGM) € 196.25 -0.49%XP Power Ltd. (DI) (XPP) 1,589.00p -0.19%