* UK gas system oversupplied by 8 mcm/d
* Sterling hit one-month low in early trade
LONDON, Aug 9 (Reuters) - British wholesale gas prices for delivery this winter and next year firmed on Tuesday morning as the pound fell to a one-month low, while prompt prices were largely flat.
Gas for Winter 2016 delivery was 0.37 pence higher at 42.47 pence per therm at 0940 GMT from the previous settlement, while Summer 2017 gas was 0.25 pence higher at 38.00 pence per therm.
"Contracts further out on the curve have firmed, taking direction from sterling losing further ground against the euro," said Andrew Crabtree, pricing and risk analyst at Wingas UK Limited.
Sterling hit a one-month low on Tuesday, hurt by comments from Bank of England policymaker Ian McCafferty who said more quantitative easing was likely to be required if the UK's economic decline worsens.
In early deals in London, sterling fell 0.5 percent to $1.2968, its lowest since July 12. It recovered a little to trade at $1.3004 after industrial data for June came in line with expectations.
Prompt prices were largely flat.
Gas for immediate delivery was 0.10 pence higher at 33.10 pence per therm at 0931 GMT from the previous settlement, while the day-ahead contract was flat at 33.20 p/therm.
However, several outages were affecting supply. Flows through the Vesterled pipeline from Norway remain at zero even though maintenance was supposed to end at the weekend.
Maintenance at the SAGE pipeline and Britannia gas field have also reduced flows. The restart of Total (LSE: 524773.L - news) 's Bacton Seal terminal has been delayed with flows expected to begin again in two days and Total's St Fergus terminal is also undergoing an unplanned outage.
Demand rose from combined cycle gas turbines and industry, as well as the residential sector but is expected to decline over the next few days as temperatures are forecast to rise to well above normal levels towards the weekend and next week.
In the Dutch gas market, the day-ahead gas price at the TTF hub rose by 0.16 euro to 12.68 euro/MWh. In the European carbon market, front-year allowances firmed 0.07 euro to 4.88 euros a tonne. (Reporting by Nina Chestney)