* Gas market 14 mcm oversupplied
* Three LNG tankers to arrive over next 7 days
LONDON, April 25 (Reuters) - British prompt gas prices fell on Monday as imports from Norway and liquefied natural gas (LNG) supplies remained strong, leaving the market oversupplied, despite strong demand amid cool weather.
Gas for within-day delivery fetched 30.75 pence per therm at 0830 GMT, down 0.75 pence from the last settlement, while gas for day-ahead delivery fell 1 pence to 30.90 pence per therm.
With (Other OTC: WWTH - news) supply flows at about 282.9 million cubic metres (mcm) and demand expected to be 268.9 mcm/day, Britain's gas system was 14 mcm oversupplied, National Grid (LSE: NG.L - news) data showed.
Monday's demand was 36 percent higher than the seasonal norm of 197 mcm/day due to colder than usual weather, which increases gas demand for heating.
However, traders said this demand was easily met due to higher imports from Norway.
Imports of gas from Norway through Langeled, Britain's main gas import pipeline, were around 35 mcm/day on Monday, up from below 30 mcm the previous day, National Grid data showed.
Imports of LNG from Qatar are also expected to ramp up this week with three tankers scheduled to arrive in Britain over the next seven days.
The Balance-of-Week (BOW) gas contract bucked the trend on Monday climbing 9 percent to 31.00 pence per therm.
Traders said liquidity in the contract was extremely low but the prospect of cool weather for the rest of the week had prompted some short-covering.
The BOW contract is a strip of daily contracts from day- ahead to the end of the working week.
British gas prices further along the curve also fell.
The Winter '16 contract fell by 0.80 pence to 35.40 pence per therm.
In the Netherlands' gas market, the day-ahead price at the TTF hub fell 0.3 euros to 12.98 euros per megawatt-hour. In Europe's carbon market, the front-year EU allowance price slipped 0.01 euros to 5.96 euros per tonne. (Reporting by Susanna Twidale)