UK GAS-Prices decline on softer demand, weaker oil

LONDON, May 5 (Reuters) - British wholesale gas prices declined on Friday morning amid softer demand and weaker oil prices. * The within-day contract was 0.30 pence lower at 40.70 p/therm. * The British day-ahead gas price was flat at 41.00 p/therm. * Traders said gas-for-power demand had weakened, but higher demand is expected next week due to colder weather. * The system was slightly oversupplied by around 3 million cubic metres (mcm), with demand at 215 mcm and flows at 218 mcm/day, National Grid (LSE: NG.L - news) data shows. * Maintenance is scheduled at Norway's Troll gas field from May 6-9 and May 15-19 which will reduce Langeled pipeline flows to 20-25 mcm/day from 40 mcm/day. * There will be a shutdown of the Ormen Lange field from May 10-14 whih will reduce Langeled flows to 10 mcm/day. * The June gas contract was down 0.30 pence at 37.30 p/therm. * Oil prices were trading around $45 a barrel, having fallen more than 3 percent at one stage, the day after dropping to five-month lows amid mounting concerns about global oversupply. * Day-ahead gas price at the TTF hub inched down by 0.05 euro to 16.15 euros per megawatt hour. * Benchmark Dec-17 EU carbon contract was down by 0.03 euro at 4.49 euros per tonne. * Thomson Reuters (Dusseldorf: TOC.DU - news) analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Nina Chestney)