The government should be doing much more to protect the environment, the Liberal Democrats have said.

Launching its environment manifesto on Tuesday, the party put tackling global warming as top of its list of priorities.

The warning came as new government figures showed that UK carbon dioxide emissions increased by 2.2 per cent in 2003.

Environment spokesman Norman Baker said the data "blows a hole through the government's climate change strategy".

"The latest figures mean we have little hope now of reaching the 20 per cent reduction target for 2010 and that we may even miss our targets under the Kyoto protocol," he warned.

"Under Liberal Democrat plans announced today, we would take positive action to tackle climate change and push for new international agreements."

The party also called for a "green backbone running right through government".

A Lib Dem government would shift the burden onto the polluter, for example by replacing air passenger duty with a charge on each aircraft.

Road user charging

Cars that pollute less would be subject to lower excise duty, adds the party.

And eventually fuel and vehicle excise duties with be replaced by road user charging.

Future energy demands would be met through a combination of energy conservation measures and renewable sources.

"We want to cut emissions from aviation by rejecting Labour's flawed plans for airport expansion; achieve real reductions in energy use by making a much stronger case for the money everyone can save, and push for strong new agreements on climate change," said Baker.

"A greener Britain means a better environment, and a better life for all."