The UK's carbon emissions rose by 1.25% last year, according to provisional government data, but Britain remains on course to meet its Kyoto Protocol goal.
High gas prices were a key factor behind the emissions rise
The main reason was a move from gas to coal for electricity generation.
Emissions of all greenhouse gases in the Kyoto deal were up about 0.5%, but are still below the target of a 12.5% cut from 1990 by the period 2008-2012.
Environmental groups say the rise shows Britain is making no real progress on cutting carbon dioxide emissions.
And Environment Secretary David Miliband said it demonstrated the need for increased action on climate change.
The UK produced total greenhouse emissions equivalent to 658.10 million tonnes of CO2 last year. This was down about 15% from the 1990 figure of 775.20 million tonnes.
Carbon dioxide output rose from 544.2 million tonnes in 2005 to 560.6 million tonnes in 2006, a significant rise compared to previous years.
The nation's CO2 output is now only 5.25% below the 1990 figure which is used as the baseline for the main Kyoto Protocol gases.
"The figures make grim reading, and show that despite the rhetoric the UK has made no real progress in cutting carbon emissions under Tony Blair's leadership," commented Mike Childs, campaigns director with Friends of the Earth UK.
Mr Miliband described the figures as "worrying".
Generating companies switched to more coal during 2006
"While these figures are provisional, they underline why concerted effort to tackle climate change, both from government and wider society, is absolutely critical," he said.
The government admitted last year that it would fail to meet its unilateral target, set before the 1997 general election, of cutting CO2 emissions by 20% between 1990 and 2010.
Instead, it said existing policies would yield a 15-18% cut over the same period, which Mr Childs described as "fanciful".
"The government dreams up estimates of what its policies can deliver without any external scrutiny; and as soon as there is any external scrutiny, they turn out to be dreams," he told the BBC News website.
Friends of the Earth is one of a number of groups lobbying for the government to adopt annual targets for carbon cuts. The recent Climate Change Bill discarded this option in favour of five-yearly targets.
THE UK'S EMISSIONS
Greenhouse gases quoted in million tonnes of CO2 (equivalent)
CO2 equivalence is calculated by multiplying the amount of each gas by its 'global warming potential'
Kyoto target is reduction of 12.5% in basket of six greenhouse gases between 1990 and the period 2008-2012
Domestic CO2 target is reduction of 20% between 1990 and 2010