THE Government last night moved to sideline environmental food zealots who have called for Britain to turn vegetarian in the battle against climate change.

As another report demanded families curb their meat and dairy consumption, the Department for Environment, Food and Rural Affairs broke cover to insist the plan had no chance of becoming Government policy.

"We are supposed to be here to support the livestock industry," said a source. "We are not going to do something which destroys that."

Environment Secretary Hilary Benn and other senior figures were known to have grown increasingly frustrated at demands from other parts of Government for diets to be altered, without regard to the efforts already being made by farmers to reduce harmful emissions.

Yesterday, the Sustainable Development Commission (SDC) said a "top priority" for Government policy must be "reducing meat and dairy consumption, reducing consumption of food and drink of low nutritional value and reducing food waste".

In its report Setting the Table – Advice to Government on priority elements of sustainable diets, the SDC admitted there were "complexities and political sensitivities to the 'meat and dairy' issue".

But the report's authors insisted the evidence of the "negative environmental sustainability impacts of livestock production is overwhelming, and includes responsibility for almost one-fifth of the world's total greenhouse gas emissions".

Tim Lang, food commissioner at the SDC, said: "Cutting down on meat and dairy, and eating only sustainably sourced fish, fruit and vegetables, would all help reduce the impact of our food system, as well as improving health."

Defra last night sought to distance itself from the study – which it commissioned. A well-placed source at the department said the report was "not particularly helpful" and "does not represent Government policy".

The tough stance from Defra comes less than three weeks after Health Secretary Andy Burnham controversially championed a report which demanded a 30 per cent reduction in livestock in high-producing countries to meet climate change targets.

Energy and Climate Change Secretary Ed Miliband and international development minister Mike Foster were also at the launch of the Lancet study, but Defra appeared to have been left out of the loop, sparking tense behind-the-scenes exchanges in Whitehall.

NFU president Peter Kendall said that if the UK Government wanted to be seen as a world leader on tackling climate change "they will need to work with farmers and not alienate them with soundbites".

Defra ministers have become increasingly strident in their support for British agriculture. The department has previously come in for criticism over the issue, with some noting that Mr Benn is a vegetarian and farming minister Jim Fitzpatrick does not eat meat either.

A Defra spokesman said: "We are working with industry to reduce emissions from the whole food chain, including those associated with the consumption of meat."