The NFU is taking on Sir Paul McCartney over a letter sent to The Independent which encouraged people to turn vegetarian.

The former Beatle teamed up with a Nobel Prize-winning scientist to write that becoming a veggie would help save the planet from the greenhouse gases created by rearing livestock.

The union has written a letter to the newspaper pointing out that adopting Sir Paul’s idea would not solve the problem and lead to other environmental problems.

“Agriculture accounts for less than one per cent of the UK’s total CO2 emissions and its methane emissions have fallen by 14 per cent since 1990, no mean feat by any industry’s standards. And practical measures to further reduce emissions from livestock are already being looked at – changing diets, managing manures and slurries more effectively, improving productivity and using anaerobic digestion to produce biogas as energy.

“If people eat less meat prices to farmers will go down. In that situation, lowland grasslands would be ploughed up to grow corn, and large parts of the uplands could be abandoned, leading to major environmental problems while having a negligible impact on the world food supply situation.

“Rather than arguing for simplistic token gestures that completely ignore the entirely understandable aspiration of people in other parts of the world for a richer and more interesting diet, we should address the root cause of the problem, which is 30 years of neglect of agricultural development.”

It is not the first time that Sir Paul has raised such an issue in the national press. A letter to the Sunday Times in 2007 prompted a flood of criticism from farmers on the FWiSpace forums.