UK GAS-Prices decline due to oversupply

LONDON, June 5 (Reuters) - British wholesale gas prices declined on Monday morning due to an oversupplied system. * British within-day gas price down 0.90 pence to 36.50 pence per therm at 0801 GMT * Day-ahead gas price 0.25 pence lower at 37.00 p/therm. * "Low demand, oversupply are putting pressure on the prompt," a gas trader said. * System oversupplied by 10 million cubic metres (mcm), with demand forecast at around 179 mcm and flows at 189 mcm/day, National Grid (LSE: NG.L - news) data shows. * Forecast demand is 28 mcm lower than the seasonal norm of 207 mcm/day. * UK Continental Shelf is close to maximum production levels, excluding Morecambe Bay which is unavailable until late August, Thomson Reuters (Dusseldorf: TOC.DU - news) analysts said. * However, flows from Norway through the Langeled pipeline are lower than on Friday due to reduced production there. * Peak wind generation is due to rise to around 8.7 gigawatts (GW) on Tuesday from around 5 GW on Monday, which could reduce demand for gas from power plants. * Prices further along the curve rose, however. The July contract was 0.58 pence higher at 37.25 p/therm. * Oil markets rose around 1 percent on Monday, pushed up by tensions in the Middle East where top crude exporter Saudi Arabia and other Arab states cut off ties with Qatar. * Day-ahead gas price at the Dutch TTF hub up by 0.35 euros to 15.00 euros per megawatt hour. * Benchmark Dec-17 EU carbon contract up by 0.08 euro to 5.24 euros per tonne. * Thomson Reuters analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Nina Chestney)