UK GAS-Prompt slips on higher Norwegian imports

* Imports through Langeled rise

* Flows through Theddlethorpe gas terminal resume

* Market almost balanced

LONDON, Sept 16 (Reuters) - British spot gas prices fell on Wednesday morning as an increase in imports from Norway helped to meet strong demand.

Gas for within-day delivery was at 41.70 pence at 0900 GMT, down 0.90 pence from the previous day's settlement.

With supply flows at 213.8 million cubic meters (mcm) per day and demand expected at 213.2 mcm, the system was almost balanced, National Grid (LSE: NG.L - news) data showed.

Wednesday's demand was around 34 percent above the seasonal norm of 159 mcm, the data showed.

Traders said cool weather forecasts led to strong demand from the gas fired power plants but the high demand was met by increased imports from Norway.

"A strong bearish driver is the surge in Langeled flows due to an ongoing maintenance affecting French receipts of Norwegian gas. This is bearish for WD (within-day) which also affects the other prompt contracts," analysts at Thomson Reuters Point Carbon said in a note on Wednesday.

Imports from Norway via the Langeled pipeline, Britain's main sub-sea gas import route, were around 70 mcm on Wednesday morning, National Grid data showed, up from levels below 40 mcm over the previous day.

Flows through Britian's Theddlethorpe gas terminal also resumed on Wednesday morning after a planned outage at the site ended.

Flows at Theddlethorpe were around 3.5 mcm/day by 0900 GMT National Grid data showed.

Gas prices further along the curve also edged higher, with the Winter 2015 contract up 0.10 pence at 43.65 pence per therm.

In the Netherlands, the day-ahead gas price at the TTF hub was 0.23 euros higher at 19.23 euros per megawatt-hour (MWh).

The benchmark European Union carbon price slipped 0.02 euros to 8.16 euros per tonne on ICE Futures Europe. (Reporting by Susanna Twidale, editing by William Hardy)