UK GAS-Prompt prices rise on lower Norwegian imports

* UK gas market 21.5 mcm undersupplied

* Flows through Langeled drop to 15 mcm

May 12 (Reuters) - British prompt gas prices rose on Thursday morning as imports from Norway dropped, leaving the market undersupplied.

Gas for within-day delivery fetched 31.55 pence per therm at 0832 GMT, up 0.90 pence from the last settlement.

Gas for day-ahead delivery rose by 1.00 pence to 31.65 pence per therm.

Norwegian imports through Langeled, Britain's main gas import pipeline, were around 15 million cubic metres (mcm), down from levels of around 27 mcm the previous day, National Grid (LSE: NG.L - news) data showed.

Imports from the Netherlands through the BBL pipeline have been at zero since the beginning of this month.

Traders said the amount of liquefied natural gas (LNG) entering the British gas system was also low, but could ramp up throughout the day to help meet demand.

"Spot prices rising significantly from yesterday's levels could incentivize higher supply from LNG," said Marcel Boonaert, head of gas trading at Wingas UK.

With (Other OTC: WWTH - news) supply flows at about 212.9 mcm and demand expected to be 191.4 mcm/day, Britain's gas system was 21.5 mcm undersupplied, National Grid data showed.

Gas prices also rose further along the curve.

The June contract rose by 0.50 pence to 30.50 pence per therm, while the Winter '16 contract was up 0.50 pence at 37.30 pence per therm.

In the Netherlands' gas market, the day-ahead price at the TTF hub gained 0.28 euro to 13.28 euros per megawatt-hour.

In Europe's carbon market, the front-year EU Allowance price rose 0.08 euro to 6.10 euros per tonne. (Reporting by Susanna Twidale; editing by Nina Chestney)