On Tuesday, Sir Keir claimed the BBC had backed him over the tax rises, prompting accusations of bias. Speaking at a press conference in Rio, where he is attending the G20 summit, the Prime Minister insisted that the “vast majority” of farmers would be unaffected.
He said: “All of you can check out what that means in terms of the impact. I think the BBC has already done it.
“It means the vast majority of farms are unaffected by this, and I think it’s just important we keep making that clear.
Meanwhile, at the protest in London, Jeremy Clarkson accused the BBC of being “a mouthpiece for this infernal Government” after a heated exchange with Newsnight’s Victoria Derbyshire.
Labour MPs have now raised concerns about the plans for the first time, urging the Government to consider making changes to protect family farms.
Figures reported by Defra are based on actual claims for agricultural property relief, while the Treasury’s analysis “goes beyond the raw data, which is where the difference is”, a government source said.
But campaigners have argued that many assets on farmland were previously claimed under business property relief – a separate tax relief scheme. From April 2026, these schemes will be joined together.
It means farmers will have to include the value of livestock, machinery and other farming assets in the value of the estate. Defra estimates that two thirds of Britain’s farms are worth more than £1m, so are potentially eligible for the tax.
An official assessment into the raid will not be published until next year’s Budget.