March 29 (Reuters) - British within-day gas prices fell on Wednesday in response to lower demand for gas to heat homes and produce electricity, and the early return of flows through the Theddlethorpe terminal.
* Within-day contract down by 0.25 pence to 38.75 pence per therm at 0849 GMT. Other prompt and forward contracts notched gains.
* Traders said lower imports from Norway and the Netherlands tightened supplies, supporting contracts further out, even as weak demand and mild weather weighed on the within-day price.
* Imports from Norway through the Langeled pipeline stayed below 60 million cubic metres (mcm) and dipped to as low as 57 mcm overnight, down from over 70 mcm on Monday.
* Flows from Britain's Bacton Seal were expected to resume flows on Thursday following an outage.
* System undersupplied by 8 mcm, with demand forecast at 226.7 mcm, and flows at 218.7 mcm/day, National Grid data shows.
* Gas deliveries from the Theddlethrope terminal returned early after a planned maintenance, currently flowing 5 mcm/day.
* ConocoPhillips' S-Area gas fields are shut until Thursday, St Fergus Mobil flows have stepped 2 mcm/day lower since Friday, and flows into Barrow terminal are due to return on May 1.
* British day-ahead gas price traded 0.10 pence higher at 38.60 p/therm.
* Two new liquefied natural gas (LNG) tankers are due to arrive in north west Europe. The Bu Samra is to unload at the UK's Isle of Grain terminal on April 9; the Al Oraiq will unload in Belgium on April 15.
* April gas contract up by 0.35 pence to 39.15 p/therm, while the Summer 17 contract up by 0.30 pence to 39.30 p/therm.
* Day-ahead gas price at the Dutch TTF hub up by 0.30 euro to 14.90 euros per megawatt hour.
* Benchmark Dec-17 EU carbon contract up by 0.04 euro to 4.70 euros per tonne.
* Thomson Reuters analyst view: here (Reporting by Oleg Vukmanovic in Milan; Editing by Edmund Blair)