UK GAS-Prices ease following rally as Qatar redirects LNG

LONDON, June 9 (Reuters) - British prompt gas prices fell on Friday as concerns eased somewhat over Qatar's redirection of two liquefied natural gas (LNG) tankers likely bound for Britain, and traders digested the impact of the change. * On Thursday, Qatar's Al Mafyar tanker turned away from the Suez Canal and now appears to be taking a longer route around Africa, delaying its arrival in Britain, traders and analysts said. * But the Zarga tanker, also from Qatar, appears to be heading towards India or elsewhere in Asia and no longer on a course towards Britain or northwest Europe. * At least one of the tankers was expected to arrive at Britain's South Hook import terminal, which has reduced output to 5 million cubic metres/day (mcm) from 9 mcm on Thursday. * British within-day gas price 0.15 pence lower at 37.60 pence per therm. Day-ahead gas 0.25 pence lower at 37.65 pence per therm. * Higher Norwegian gas flows to the UK also pressured prompt contracts, Thomson Reuters (Dusseldorf: TOC.DU - news) analysts said. Flows via Norway's Langeled pipeline are up 3 mcm at 21 mcm/day. * Demand is forecast at 176.3 mcm and flows at 168.5 mcm/day, leaving the system undersupplied by 7.8 mcm, National Grid (LSE: NG.L - news) data shows. * UK Continental Shelf supply fell by 4 mcm to 137 mcm. * July gas contract - lifted the most by Thursday's LNG-led rally - was down 0.47 pence at 37.25 p/therm. * Day-ahead gas price at the Dutch TTF hub up 0.05 euro at 15.13 euros per megawatt-hour. * Benchmark Dec-17 EU carbon contract down 0.03 euro at 5.02 euros a tonne. * Thomson Reuters analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Oleg Vukmanovic; Editing by Dale Hudson)