The Scottish Government last night bowed to pressure from political opponents and the Green lobby and increased their target to cut carbon emissions by 42% by 2020.

The Scottish Government last night bowed to pressure from political opponents and the Green lobby and increased their target to cut carbon emissions by 42% by 2020.

But ministers made clear that the new target, which will be enshrined in tomorrow's Climate Change Bill, will have conditions set on it regarding EU and UK measures which could impinge on Scotland's ability to lead the way in terms of climate change.

Ministers last night introduced a manuscript amendment, to raise the ante on a Labour amendment specifying 40% as a target.

The effect will be that a 34% cut with the option to boost that to 42% under certain conditions will be reversed - to a 42% target on the face of the bill subject to expert advice that external factors make that possible.

Labour had backed the 34% target in committee but then in recent days had switched to calling for a 40% figure, with the backing of the Greens, LibDems and climate change campaigners.

This made a defeat for the government a real prospect.

Faith leaders last night threw their weight behind the campaign to force the Scottish Government into the 11th-hour change. Kirk Moderator the Right Rev Bill Hewitt, Cardinal Keith O'Brien of the Catholic Church, and Imam Muhammad Ruzwam representing Muslims and others appealed to the government to accept an amendment toughening the emissions targets.

They wrote in a letter to The Herald: "Climate change is both an issue of poverty and injustice.

"Our moral traditions commit us to protecting human life and dignity, especially of the poorest, most vulnerable members of the human family.

"Although climate change has been caused by the emissions of the wealthiest nations, our respective aid agencies (Christian Aid, SCIAF and Islamic Relief) are currently witnessing its disproportionate and devastating effects on the world's poorest communities."

Their letter adds: "We congratulate the Scottish Parliament on taking forward this crucial piece of legislation and urge all MSPs to support measures in the bill which will ensure Scotland takes its fair share of the global effort required to avoid dangerous climate change."

Ministers had been proposing to match the UK reductions limit of 34% by 2020, but to build in several enhancements to the bill, including a 42% reduction if the Copenhagen Agreement sets a new 30% level EU, recognition of carbon consumed in Scotland rather than simply created here, and the inclusion of maritime and aviation emissions which do not apply to Westminster targets.

But Oxfam, one of the lead groups within the Stop Climate Chaos Scotland coalition who are planning a demonstration at Holyrood tomorrow, say that the problem with the proposed bill was that it failed to take a unique opportunity to put pressure on Europe. "You need to lead rather than be led," said Oxfam's Michael Marra.