UK GAS-Day-ahead prices rise as maintenance cuts supply

* UK gas market 12.4 mcm undersupplied

* Maintenance at CATS cuts supply

LONDON, June 6 (Reuters) - British prompt gas prices rose on Monday as maintenance at the country's gas pipeline system curbed supply.

Gas for day-ahead delivery traded at 35.35 pence per therm at 0833 GMT, up 0.65 pence from their last settlement.

"Supply has is substantially reduced due to start of planned maintenance at CATS (the U.K.'s Central Area Transmission System) terminal and pipeline from this morning, which impacts Teesside BP and Teesside PX negatively," said gas analysts at Thomson Reuters (Dusseldorf: TOC.DU - news) .

Flows through the Teesside BP terminal were at zero, down from around 8 million cubic metres (mcm) the previous day.

Flows from the Teesside PX terminal were at around 2 mcm.

With total British supply flows at 144.8 mcm and demand expected to be 157.2 mcm/day, Britain's gas system was 12.4 mcm undersupplied, National Grid (LSE: NG.L - news) data showed.

Demand is below the seasonal norm due to a rise in temperatures.

Further along the curve, gas prices also rose.

Traders said the near-term gas contracts were buoyed by an absence of any liquefied natural gas (LNG) tankers scheduled to arrive in Britain over the next few weeks.

The July contract rose 0.75 pence to 33.55 pence per therm, while the Winter '16 gas contract climbed by 0.75 pence to 39.10 pence per therm.

In the Netherlands' gas market, the day-ahead price at the TTF hub was up 0.15 euro at 14.43 euros per megawatt-hour.

In Europe's carbon market, the front-year EU allowance price gained 0.11 euro to 6.06 euros per tonne. (Reporting by Susanna Twidale; editing by Nina Chestney)