The Government has been accused of dealing a “hammer blow” to farmers as 13,000 people protested in Whitehall over the Budget’s impact on farming.

TV presenter and journalist-turned-farmer Jeremy Clarkson made the comments as he joined thousands of people in central London to protest against changes to inheritance tax for farm businesses and other measures in last month’s Budget.

The rally, which was attended by an estimated 13,000 people, according to police, was held alongside a mass lobby of MPs by members of the National Farmers’ Union (NFU).

Farmers have reacted with anger and dismay to the inheritance tax changes for farming businesses, which limit the existing 100% relief for farms to only the first £1 million of combined agricultural and business property.

But ministers have said farmers are “wrong” to think that thousands of farm businesses will be affected by the changes, insisting only around 500 of the wealthiest estates will have to pay tax under the move.

The Government has also said they had put a record £5 billion aside over two years for sustainable farming, but farmers warn of of the impact of speeding up the phase-out of EU-era subsidies as funding is switched to nature-friendly land management schemes, and other measures in the Budget.

Some farmers warn they will have to sell off land to meet the inheritance tax costs and are threatening to strike over the pressures they say they are being put under by Government policy, while there are warnings over people’s mental health.

Addressing the rally, Clarkson said: “I know a lot of people across the country in all walks of life took a bit of a kick on the shin with that Budget.

“You lot got a knee in the nuts and a hammer blow to the back of the head.”

He urged ministers to back down over inheritance tax.

“For the sake of everybody here, and for all the farmers stuck at home paralysed by a fog of despair over what’s been foisted on them, I beg of the Government to be big and accept this was rushed through, it wasn’t thought out and it was a mistake,” he said.

And he told the PA news agency: “If she (Rachel Reeves) would have wanted to take out the likes of James Dyson and investment bankers and so on, she would have used a sniper’s rifle, but she’s used a blunderbuss and she’s hit all this lot.”

The human impact of this policy is simply not acceptable, it’s wrong

NFU president Tom Bradshaw told members in a speech before they met with MPs that the policy was “kicking the legs out from under British food security” and was putting “horrendous pressure on the older generation of farmers who have given everything to providing food for this country”.

To sustained applause as he became emotional, he said: “The human impact of this policy is simply not acceptable, it’s wrong.

“Our request is very simple, this is a policy that will rip the heart out of Britain’s family farms, launched on bad data with no consultation, and it must be halted and considered properly.”

And he told journalists that Rachel Reeves had refused to engage with the NFU on the issue, adding: “The human impact of this policy is one I don’t believe they intended but the longer they leave this hanging, the more I start to think it’s vindictive, rather than miscalculated.”

But a Government spokesperson said ministers from both Treasury and the Environment Department (Defra) had regularly engaged with the NFU.

And ministers have defended the inheritance tax changes, with Prime Minister Sir Keir Starmer reiterating his stance that the “vast majority” of farms will be “totally unaffected” by changes to inheritance tax.

If farmers look at the facts they will see the vast majority of them will pay nothing more under the new scheme

Environment Secretary Steve Reed told the PA news agency that only a few hundred farms would be impacted, rather than the tens of thousands claimed by critics of the inheritance tax change.

“If farmers look at the facts they will see the vast majority of them will pay nothing more under the new scheme than they did under the old scheme,” he said.

In an appearance before MPs in the Environment, Food and Rural Affairs Committee on Tuesday, Mr Reed said, based on projections from the Treasury, many farmers who thought they were going to be affected “probably happily, are wrong”.

“The numbers I’ve heard bandied around are enormous and very, very frightening if people were to believe them,” he said.

And he cautioned against using figures based on Defra data on the value of farms to assess how many farmers might be liable for inheritance tax, saying “you can’t do that, because ownership is much more complex than one person, one farm”.

Outside Parliament, children on toy tractors led a small march, while the majority of protesters gathered along Whitehall listening to speeches.

Many held signs and banners, including ones that said “Starmer the farmer harmer” and “no farmers no food no future”.

MPs Nigel Farage, Kemi Badenoch and Sir Ed Davey were among the thousands of people in London for the farmers’ protest.

Sir Ed told farmers in Whitehall “you deserve so much better”.

Meanwhile, Mr Farage told farmers at the protest: “I can feel myself that today is not just about inheritance tax. It really is farmers versus Starmer.”

Speaking to the PA news agency, shadow environment secretary Victoria Atkins said she had “real-life examples” such as one elderly farmer considering whether “it would be better for him to pass away” before the inheritance tax changes come through.

“These are conversations that are being had up and down the country on our farms, and I gave this example last night to ministers – they had no answer.

“That is why farmers are here today.

“In anguish, in distress, and some in anger, because they see not just their livelihoods today affected by this, but the livelihoods of their children,” she said.

The Metropolitan Police said there had been no arrests linked to the protest, but tractor drivers who ploughed through barriers at the farmers’ protests in central London will be reported.