Labour’s “war on farmers” has been slammed for jeopardising food security as opponents prepare to protest against the Government’s inheritance tax raid.

Transport Secretary Louise Haigh revealed that plans exist to deal with food shortages if farmers go ahead with their threat to strike over a family farm tax.

But when challenged by the Daily Express over fears of empty shelves, Prime Minister Sir Keir Starmer insisted “the vast majority” of farmers wouldn’t be impacted by tax changes.

Shadow Home Secretary Chris Philp said the rise in inheritance tax is a “war on farmers” that will “undermine our food security”.

Farmers are often “struggling to make ends meet”, he said.

The MP added: “So the fact that Labour has declared war on farmers is obviously bad for farmers, but it’s actually bad for all of us, because it’ll undermine our food security.”

About 20,000 farmers will descend on London on Tuesday to protest against plans to impose a 20% inheritance tax on farms worth £1million or more.

They have warned that the policy will destroy family farms across the country and could see them broken up.

Welsh campaign group Enough is Enough has called for a national strike among British farmers to stop producing food until the decision to impose inheritance tax on farms is reversed.

The Daily Express has launched the Save Britain’s Family Farms crusade and has called for Chancellor Rachel Reeves to U-turn.

National Farmers’ Union president Tom Bradshaw said: “I think the industry is feeling betrayed, feeling angry.

He told Sky News’s Sunday Morning with Trevor Phillips: “We have a Government saying food security is a critical part of national security, yet they’ve ripped the rug out from that very industry which is going to invest in food security for the future.”

But he said he did not “for one moment condone” withholding food from supermarkets in protest.

“That is not an NFU tactic, we do not support emptying supermarket shelves,” he said.

“But I do completely understand the strength of feeling that there is amongst farmers. They feel helpless today, and they’re trying to think of what can they do to try and demonstrate what this means to them.

“So look, I understand their strength of feeling, but we are not supporting that action.”

As he travelled to Rio for the G20 Summit, Sir Keir told reporters that he understands farmers’ frustrations over tax changes.

Asked if farmers would be physically removed if they occupied streets like Just Stop Oil protesters, the Prime Minister said: “They are entitled to express their views. I do understand their concerns.

“It’s important I reiterate the support that is going in, it is quite considerable.

“As to how the protest takes shape and what the response is, that will be a matter for them and the police for how they respond to it.”

He said that “for a typical case, which is parents with a farm they want to pass on to one of their children, by the time you’ve taken into account not only the exemption for the farm property itself, but also the exemption for spouse to spouse, then parent to child, it’s £3million before any inheritance tax will be payable”.

He added: “That’s why I am absolutely confident the vast majority of farms and farmers will not be affected by this.

“It’s important for us to keep communicating how that works. Over the £3million, it’s then 20% rather than the usual rate and it’s payable over 10 years.

“The threshold for a typical case is £3million.”

Asked about contingency plans for food security if farmers strike, Ms Haigh said: “The Department for Environment, Food and Rural Affairs will be setting out plans for the winter and … setting out contingency plans and ensuring that food security is treated as the priority it deserves to be.”

Tory party chairman Nigel Huddleston said the Transport Secretary dismissed the concerns of farmers by failing to understand the impact the family farms tax will have on rural communities and price rises.

He said: “As Keir Starmer jets off to Brazil this week on his latest international trip, he seems oblivious to the challenges facing Britain’s farming community, small businesses, charities and care sector that have been caused by Labour’s disastrous, tax-raising Budget.”

Treasury data show that about three quarters of farmers will pay nothing in inheritance tax as a result of the controversial changes announced in the Budget last month.

But farmers have challenged the figures, pointing instead to data from the Defra which suggest 66% of farm businesses are worth more than the £1million threshold at which inheritance tax will now need to be paid.

Former environment secretary Steve Barclay said: “Labour’s decision to press ahead with a family farm tax will cause serious damage to Britain’s agriculture sector.

“It will force farmers out of business, in turn increasing costs for consumers in the shops, and ultimately put our food security at risk in an increasingly uncertain world.”