UK GAS-Prompt prices slip on ample supply, mild weather

* System 5 mcm long - National Grid (LSE: NG.L - news)

* Temperatures forecast above average in coming 2 weeks

LONDON, Dec 8 (Reuters) - British gas prices eased on Tuesday as ample supplies easily met demand, with mild weather limiting demand for gas for heating needs.

Gas for next-day delivery eased 0.05 pence per therm to 36.75 pence per therm by 0950 GMT, while gas for within-day delivery was unchanged at 36.55 pence per therm.

The system was 5 million cubic metres (mcm) oversupplied, with demand forecast at 245 mcm, while supply was pegged at 250 mcm, National Grid data showed.

Demand was well below the seasonal norm of 272 mcm.

The Met Office forecast temperatures of around 12 or 13 degrees on Tuesday, above seasonal norms, before dropping to five or six degrees later in the day.

Consultants Energy Aspects said in a note that weather in the U.K. and Continental Europe was forecast to be "broadly warmer than average" over the coming two weeks.

"The demand outlook is still unsupportive of gas prices."

Flows via the Langeled pipeline between Norway and Britain were around 51 mcm per day, below full capacity of around 72 mcm per day, with scope to rise if U.K. demand picked up.

Gas prices for January fell 0.2 pence to 37.00 pence/therm.

In the Netherlands the day-ahead gas price at the TTF hub was down 0.15 euros to 16.63 euros per megawatt hour.

In Europe's carbon market the benchmark EU Allowance (EUA) edged down 0.03 euros to 8.38 euros a tonne. (Reporting by Sarah McFarlane; editing by Louise Heavens)