SCOTTISH Gas delivered a blow to more than 1million Scots households today by confirming it will hike gas and electricity tariffs by 6% next month.

Centrica-owned British Gas, and its subsidiary Scotttish Gas, said the annual dual fuel bill for customers with average consumption will increase by around £80 to £1318.

A total of 8.5m UK households will be hit, although another 1m British Gas customers on fixed price contracts will be unaffected.

British Gas managing director Phil Bentley said rising costs – that are largely outside its control but which make up most tariffs – were to blame.

However, the pre-winter increase comes just months after it announced a 23% leap in half-year profits at its residential arm to £345m.

Rival SSE, which trades as Southern Electric, Swalec and Scottish Hydro, is due to increase tariffs by 9% on average on Monday, hitting 5m electricity customers and 3.4m gas customers.

Mr Bentley said: "Britain's North Sea gas supplies are running out, and British Gas has to pay the going rate for gas in a competitive global marketplace.

"Furthermore, the investment needed to maintain and upgrade the national grid to deliver energy to our customers' homes, and the costs of the Government's policies for a clean, energy-efficient Britain, are all going up."

Ann Robinson, director of consumer policy at uSwitch, said the increase would leave many households facing a winter where they are "scared to turn on heating for fear of the cost".

Centrica said prices in the wholesale market for gas this winter are around 13% higher than those paid for the same period last year.

Assuming normal weather and despite the price rise, Centrica said British Gas Residential profits for the second half of this year are expected to be around 15% lower than for the same period last year.

Unions and consumer groups called on the Government to take urgent action to tackle rising fuel prices.

Unite general secretary Len McClusk-ey said: "Money from the poor is going to the pockets of Centrica shareholders.

"This is further shameful abuse by out of control, greedy fuel companies sitting on piles of profit."