* Rough storage closure, sterling losses drive exports
* Spot prices down 0.25 pence at 33.75 pence/therm
By Oleg Vukmanovic
July 20 (Reuters) - British spot gas prices fell on Wednesday as excess supply created by a major cut in inventory restocking pushed exports to Europe to the highest monthly rate since at least 2011.
The closure of Britain's largest gas reservoir Rough until March next year released large volumes of gas earmarked for storage onto the open market, stimulating exports to Belgium through a under-sea gas link.
Sterling's sharp drop against the euro also makes UK gas even cheaper for European buyers, helping sustain a 1 penny spread between British and European day-ahead gas prices.
The highest ever daily flow was in July 2013 at 59 million cubic metres/day (mcm), while the peak so far this month was 57 mcm/day, Saratzis said.
Gas for instant delivery was at 33.75 pence per therm at 0913 GMT, down 0.25 from Tuesday's close. Day-ahead gas edged up 0.05 pence to 34 pence per therm.
The gas grid was marginally oversupplied with demand estimated at 179.2 million cubic metres/day (mcm) and supply at 180 mcm/day, National Grid data showed.
While supply coming into Britain from offshore fields and Norway steadied overall, flows into the Barrow terminal stayed at zero after Centrica (LSE: CNA.L - news) extended an outage at its North Morecambe gasfield to July 23.
Further out on the curve, the benchmark winter 2016 contract slipped by 0.01 p/therm to 45.49 p/therm.
"Contracts into the near curve are continuing to find support, with sterling holding Tuesday's losses against the euro ahead of static expected results from UK unemployment data," Marcel Boonaert, head of trading and portfolio at Wingas UK, said.
In Europe's carbon market, the front-year EU allowance price was down 0.01 euro at 4.66 euros per tonne.
Carbon prices have fallen almost 20 percent since Britain voted to leave the European Union on June 23 on fears the country, which is a major buyer of EU carbon allowances, could also leave the bloc's Emission Trading System.
In the Netherlands, the day-ahead price at the TTF hub was up 0.10 euro at 14.35 euros per megawatt-hour. (Reporting by Oleg Vukmanovic; editing by Alexandra Hudson)