Too many Scots are spending too much of their income on their power bills.

As The Herald reveals today, Scotland has 658,000 households living in fuel poverty (using more than 10% of their income to pay their energy bills). That is almost exactly twice as many as in London, even though the English capital boasts a population of 7.5 million, compared to just 5.25m in Scotland. The figures were unearthed by the Scottish Labour MP Tom Greatrex.

There are three major reasons for the discrepancy. The first is that Scotland's harsher climate means that the average annual energy bill is £300 higher in Inverness than the south of England. Secondly, Scotland has a disproportionate number of hard-to-heat homes, largely because about a third of them, including the thousands of sandstone and granite blocks, are not suitable for cavity wall insulation. Inevitably, this impacts on the country's greenhouse gas emissions, which rose by 1.9% in 2010, making the Scottish Government's ambitious target of reducing emissions by 42% by 2020 appear unachievable. Thirdly, many homes are beyond the gas mains, leaving householders to rely on all electric systems or bottled gas, which are generally more expensive.

There are several important implications to be drawn from these figures. The first is that schemes such as winter fuel payments for pensioners that are based on flat rate payments are grossly unfair to Scots, especially those living in cold homes in the north.

Also, though modern building regulations mean that new houses are reasonably energy efficient, most of us will continue to lives in homes that pre-date those changes for decades to come. And, though fuel efficiency certification and progress in areas like loft lagging are improving matters, far more needs to be done to help those on low incomes in the most hard-to-heat homes.

In addition, there are too few too large energy suppliers in Britain and their prices tend to rise and fall in tandem, often rising like rockets and falling like feathers, long after the wholesale price has gone down. A full Competition Commission inquiry is overdue. And small suppliers should be encouraged to enter the market. Meanwhile, Ofgem must put pressure on suppliers to offer, not only pensioners, but other vulnerable and low income customers the lowest tariffs.

The Scottish Government's pledge to tackle ageing houses and cut power bills sounds good but the administration should be judged on its achievements rather than its intentions and recently fuel poverty has increased.