More than half of rural voters trust Labour less after the Budget, a poll has found, as the head of a countryside business association warned the party faced “irreversible” damage to its support.

Victoria Vyvyan, president of the Country Land and Business Association (CLA), said the decision to impose a 20% inheritance tax on some farms “threatens business viability and the future of our rural communities”.

She said: “The Government promised growth, and to be the ‘party of the countryside’, but you can’t tax your way to prosperity.”

Her comments follow the publication of a poll, commissioned by the CLA, that showed 23% of Labour voters in the countryside were now unhappy with their decision while 48% said they were still happy.

Some 57% said the decision to impose inheritance tax on some farms had led them to trust Labour less while 61% said the party was breaking its promise to “end the decline of our countryside”.

Ms Vyvyan said: “Trust, once lost, is hard to win back. Can Labour regain it? Only with a sincere apology, real action and a clear commitment to the rural economy.

“Anything less, and the damage could be irreversible.”

July’s general election saw Labour pick up a significant number of rural seats as support for the Conservatives declined.

But the CLA’s poll of the 100 most rural seats in England suggested the party had lost support since then and was now joint second with Reform UK in those seats.

The poll follows weeks of protests by farmers, including a mass rally in Westminster calling for the inheritance tax changes to be reversed.

Environment Secretary Steve Reed later told the CLA he had “heard the anguish of the countryside”, and the Prime Minister met the president of the National Farmers’ Union on Monday to discuss the issue but so far the Government has insisted it will not reverse course.

A Government spokesperson said: “Our commitment to farmers and rural communities remains steadfast.

“We are investing £5 billion into farming over two years – the largest budget for sustainable food production in our country’s history.

“We are going further to support rural communities by turbocharging rural economic growth, introducing the first-ever rural crime strategy and lowering energy bills for rural households through GB Energy.

“Our reform to agricultural and business property relief will impact around 500 estates a year. For these estates, inheritance tax will be at half the rate paid by others, with 10 years to pay the liability back interest free.

“This is a fair and balanced approach which fixes the public services we all rely on.”

The CLA poll was carried out by Survation between November 14 and 21, and surveyed 1,092 adults living in the 100 most rural constituencies in England.