UK GAS-Prices climb on fears of Russian supply cut, colder weather

* Fears of Russian supply cut support market

* Temperatures expected to fall slightly

* LNG tanker arrivals mean ample supply

LONDON, April 8 (Reuters) - British wholesale natural gas prices climbed on Tuesday morning (Frankfurt: TDM.F - news) on fears tension between Russia and Ukraine could disrupt Russian gas supplies to Europe and prospects for colder weather.

Ukrainian police detained 70 pro-Moscow protesters occupying a regional administration building in eastern Ukraine overnight, while Russia's Foreign Ministry warned Kiev against using force against pro-Russian demonstrators.

Russian troops are massed on the border with Ukraine, a major transit route for Russian gas to Europe.

Gas for next-day delivery rose to 52.15 pence per therm at 0905 GMT, up 0.45 pence from Monday's close, after rising steeply on Monday afternoon.

Intra-day gas was up 1.33 pence at 52.53 pence per therm.

According to data from National Grid (LSE: NG.L - news) , Britain's gas system was broadly balanced on Tuesday morning, with forecast flows of 197.9 million cubic metres (mcm) and demand of 199 mcm.

But meteorologists said they expected average British temperatures to drop towards the seasonal norm over the next two weeks, likely boosting demand.

"With cooler UK weather, prices could see better support around current levels, and the promised loss of so much Norwegian production for May does mean the market seems a bit tighter," Energy Aspects said in a research note on Tuesday.

Norway is planning several maintenance shutdowns in May, reducing available capacity, according to Norwegian pipeline operator Gassco. (http://flow.gassco.no)

On Tuesday, a sharper rise in prices was prevented by high sendouts of about 36 mcm per day from the South Hook liquefied natural gas (LNG) terminal in Wales, where the tanker Al Gharrafa is moored.

Two further LNG tankers are scheduled to arrive in Britain by April 15, meaning Britain's gas markets will likely remain amply supplied into next week.

In Britain's power markets, prices for baseload (24 hours) delivery rose by 2 pounds ($3.32) per megawatt-hour to 41 pounds per MWh as wind power production declined.

($1 = 0.6020 British Pounds)

GAS UK natural gas prices National Grid instant flows National Grid gas demand North Sea gas and power maintenance

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(Reporting by Alexander Winning)