Anger at rising fuel bills after gas firm posts £1.3bn profits
The firm was accused of "profiting at the expense" of hard pressed Scots, after it emerged British Gas's parent company Centrica recorded profits of more than 1.3 billion in the first half of 2011.
Consumer groups described a hike in the average British Gas annual household bill from 543 to 1,286 between 2004 and 2011 as "incredibly worrying", while energy prices regulator Ofgem suggested that customers paying heavy rates should consider switching their supplier.
The figures revealed by energy experts uSwitch.com came after British Gas was fined 2.5 million for failing to sort out customers' problems by industry watchdog Ofgem, which said it found "basic failures" in the under-fire company's complaints procedures.
Average household bills in the UK for British Gas customers for January 2004 stood at 543, with increases to 642 and 735 for the same period in 2005 and 2006.
By January 2007 average bills for families were up to 1,002 and although charges fell the following year to 821, at the start of 2009 prices went up to 1,176.
The average bills for January 2010 and 2011 were 1,066 and 1,096 respectively, before sharp rises in fuel prices announced by British Gas mean cutomers could now face peak bills of 1,286.
Trisha McAuley, depute director at Consumer Focus Scotland, said that customers were "bound to questions about whether recent large price hikes were necessary", due to the high profits posted by Centrica.
She said: "It's incredibly worrying that the prices of energy bills for consumers in Scotland have gone up so dramatically in the last few years."
SNP MSP John Wilson, the deputy convenor of the Scottish Parliament's economy committee called on the UK government to take action to bring fuel prices under control.
Mr Wilson said: "The figures released by uSwitch bear out the fears that many consumers have expressed about energy bills.
"At the same time as energy bills are increasing the profits of Centrica are not affected. These companies are clearly profiting at the expense of the consumer.
"The UK government and Ofgem must now take action to ensure hard-pressed consumers don't have to pay for the profits of companies like Centrica."
Ann Robinson, director of Consumer Policy at uSwitch.com said that the 134 per cent increase in fuel bills between 2004 and 2011 was "unacceptable", forcing people into "fuel poverty".
She said: "Since 2004 energy bills have rocketed by 134 per cent, from 522 a year to 1,222 a year on average.This is astonishing, but goes some way towards explaining why energy bills are becoming a growing concern for consumers.
"The danger is that for many, energy will become a luxury instead of the household essential it really is. This is unacceptable.
"We already have 6.3 million households living in fuel poverty and with each price hike, ever more households are being pushed into this trap."
An Ofgem spokesman said: "It's important people look for the best deal. There are savings that can be made by people switching their energy supplier."
A British Gas spokeswoman blamed soaring fuel bills on rising global energy costs.