Over 150,000 people have signed a petition calling on the government to reverse its deeply controversial decision on agricultural property relief (APR).
Calls to overturn the tax change - dubbed the 'family farm tax' - have gathered pace after the NFU launched a viral campaign following last week's autumn budget.
Tens of thousands of people have been adding their names to the campaign, which warns that if the change goes ahead, it will deal a 'hammer blow' to families.
It comes after the Chancellor Rachel Reeves announced in the budget that farmers would have to pay 20% inheritance tax on farms worth more than £1m.
This has left many families fearing they would have to break up their farm to pay the bill.
Labour's announcement was made despite multiple warnings from farming groups for the government not to make any changes to APR.
Immediately after the announcement, NFU President Tom Bradshaw said it needed to be 'overturned, and fast'.
He said: “Farmers are rightly angry and concerned about their future and for the future of their family farms, having been reassured by ministers in the lead up to the budget that APR changes were not on the table.”
The farming community have taken to social media to express their anger and frustration at the announcement and backed NFU calls for an immediate u-turn.
On social media, arable farmer Tom Allen Stevens said: “Congratulations for launching this petition on the family farms tax and reaching the 100,000 target.
"Consumers know there is a better way to support public services than tax cash-poor farmers.”
Another farmer, Tracy Graham, added: “Signed and shared. Everyone able to sign this really should.
"This is the single most important petition I feel I have ever signed. Thank you to all our farmers.”
It comes as farmers across the UK are set to descend on central London later this month as part of a rally against the budget.
Organised by the NFU, the 'mass lobby of MPs' will take place at the Church House conference centre in Westminster, on Tuesday 19 November.
The Country Land and Business Association (CLA), which represents landowners, has also launched a campaign, calling on the public to 'defend' family farms.
The body warned that the budget had the potential to be 'deeply damaging' for British farming, land management, food security and environmental recovery.
