Carbon dioxide emissions from Britain's power stations have grown markedly in recent years, a report has concluded.
Coal remains a staple fuel for many economies
Commissioned by the environmental group WWF from consultants IPA, it found that UK power sector emissions rose by nearly 30% between 1999 and 2006.
As gas prices have risen faster than coal, generating companies have used more of the higher carbon fuel.
WWF says that the "dash for gas" of the early 1990s has been replaced by a de facto "roll to coal".
UK power sector emissions were 6% higher in 2006 than in the preceding year, it said.
The government admitted that emissions have risen in recent years, but said that could be tackled with new initiatives.
"This is a disgrace for Britain, and shows that for the past decade the government has talked a good game on climate change while failing dismally to tackle emissions from this highly polluting sector," said Keith Allott, head of climate change at WWF UK.
"If the government is serious about climate change, the power sector has to be brought to heel, either through incentives or legislation, so that coal burn is dramatically reduced."
In the early 1990s, the opening up of North Sea reserves prompted a move to gas, which saw coal-fired power stations close and cleaner gas-fired plants spring up in their place.
Carbon emissions fell as a result - the main reason why Britain was able to adopt a relatively strict Kyoto Protocol target.
"Emissions from electricity generation are down substantially on 1990 levels, the base year for our Kyoto target," said a spokeswoman for the Department of Trade and Industry (DTI).
"They have risen more recently, something we are aiming to stem through measures to bring on more low-carbon energy.
"Renewable energy in the UK has been growing at a rapid rate over recent years, from only 1.5% in 2001 to almost 5% today, and in May we'll publish our Energy White Paper to develop this and other low-carbon forms of energy even further."
Since 2002, coal prices have risen by about one-third and gas prices by two-thirds, with gas showing a lot more volatility.
The various mechanisms designed to bring down emissions, such as the UK's Renewables Obligation and the European Union's Emissions Trading Scheme (ETS), have not been enough to combat this financial pressure towards coal.
"It is conceivable that without these measures, emissions from the power sector would have been much higher," the report suggested.
"However, the policy framework has clearly been insufficient to put the power sector onto a downward path."
IPA sees a high price for carbon as a key driver towards lowering emissions in the power sector.
The government admitted last year that it would fail to meet its longstanding commitment to reduce CO2 emissions by 20% from 1990 levels by 2010.
WWF said that even the government's longer-term targets, announced in the Climate Change Bill earlier this month, of CO2 reductions of about 30% by 2020 and 60% by 2050, would be in doubt unless it curbed the growth in coal burning for electricity.