* UK gas market 18.6 mcm undersupplied
* Flows through Langeled drop to 13 mcm
May 24 (Reuters) - British prompt gas prices rose on Tuesday morning, as imports from Norway dropped, leaving the market under-supplied.
Gas for within-day delivery fetched 30.35 pence per therm at 0852 GMT, up 0.60 pence from the last settlement.
With (Other OTC: WWTH - news) supply flows at about 198.8 million cubic metres (mcm) and demand expected to be 217.4 mcm/day, Britain's gas system was 18.6 mcm under-supplied, National Grid (LSE: NG.L - news) data showed.
Norwegian imports through Langeled, Britain's main gas import pipeline, were around 13 million cubic metres (mcm), down from levels of around 40 mcm the previous day, the National Grid data showed.
Imports from the Netherlands through the BBL pipeline have been at zero since the beginning of this month.
Gas prices nudged lower further along the curve.
"Prices further out on the curve have softened marginally, taking direction from a tick up in sterling against the euro and front-month Brent crude trading lower," said Marcel Boonaert, head of gas trading at Wingas UK.
The Winter '16 gas contract was down 0.40 pence at 35.00 pence per therm.
In the Netherlands' gas market, the day-ahead price at the TTF hub gained 0.07 euro to 12.90 euros per megawatt-hour.
In Europe's carbon market, the front-year EU allowance price was flat at 5.74 euros per tonne. (Reporting by Susanna Twidale; editing by Adrian Croft)