UK GAS-Day-ahead prices at highest since March 2015

* Consumption sharply up-analysts

* Day-ahead at 57 p/therm, highest since March 26, 2015

* Demand 26 mcm above seasonal norm

LONDON, Jan 12 (Reuters) - British day-ahead prices reached their highest level since March 2015 on Thursday, as low temperatures for the next few days prompted more demand for heating.

Gas for day-ahead delivery was up 1.80 pence at 57.00 pence per therm at 1120 GMT, its highest level since March 26, 2015.

Gas for immediate delivery was 1.80 pence higher at 56.00 pence per therm and the weekend contract was 2.00 pence higher at 56.40 p/therm.

"Consumption is forecast up sharply for most contracts," said Francois Flament, analyst at Thomson Reuters (Dusseldorf: TOC.DU - news) .

Temperatures are forecast at a maximum of 7 degrees Celsius on Thursday in southeast England, with snow likely in the evening and falling to a minimum of -4 degrees Celsius overnight, the Met Office said.

Temperatures are then seen at a maximum of 5 degrees on Friday and there could be slightly milder conditions at the weekend, it added.

Demand was around 26 million cubic metres (mcm) above the seaonal norm, National Grid (LSE: NG.L - news) data showed.

The system was actually oversupplied by around 16 mcm on Thursday, with flows forecast at 345 mcm and demand at nearly 329 mcm/day.

Import flows through the InterconnectorUK (IUK) pipeline were up sharply, and Norwegian and UK Continental Shelf supplies were steady.

"IUK is expected to remain within a corridor of 20 to 40 mcm/d while the BBL (Shenzhen: 002776.SZ - news) pipeline (from the Netherlands) is forecast to go up to 25 mcm/d when demand is at its highest," Flament said.

In the Netherlands, the day-ahead gas price at the TTF hub was 0.55 higher at 21.00 euros/MWh, its highest level since the end of July, 2015.

In the European carbon market, the benchmark Dec (Shanghai: 600875.SS - news) . 17 contract was 0.23 euro lower at 5.30 euros a tonne. (Reporting by Nina Chestney)