* UK gas market 22.3 mcm undersupplied
* Flows through Langeled drop to around 20 mcm
June 15 (Reuters) - British prompt gas prices rose on Wednesday morning, as imports from Norway dropped, leaving the market under-supplied.
Gas for within-day delivery fetched 35.50 pence per therm at 0823 GMT, up 2 pence, or 6 percent from the last settlement. Day-ahead gas prices rose by 1.25 pence to 35.00 pence per therm.
With (Other OTC: WWTH - news) supply flows at about 162 million cubic metres (mcm) and demand expected to be 184.36 mcm/day, Britain's gas system was 22.3 mcm under-supplied, National Grid (LSE: NG.L - news) data showed.
Norwegian imports through Langeled, Britain's main gas import pipeline, were around 20 million cubic metres (mcm), down from levels of around 70 mcm the previous day, National Grid data showed.
Norway's Kvitebjorn gas field is experiencing an unplanned outage which has cut production by 6.9 mcm/ day, operator Gassco said.
Ongoing yearly maintenance at the Emden terminal has also curbed the country's gas output by 34.4 mcm, Gassco's website showed.
Gas prices also rose further along the curve. The Winter '16 gas contract was up 0.60 pence at 40.65 pence per therm.
In the Netherlands' gas market, the day-ahead price at the TTF hub gained 0.37 euro to 14.50 euros per megawatt-hour.
In Europe's carbon market, the front-year EU allowance price was up 0.06 euro to 5.92 euros per tonne.
(Reporting by Susanna Twidale; editing by Nina Chestney)