Speaking on a visit to a farm in Bangor, County Down, she described the tax rise as a “family farms tax” and called for it to be reversed.

In the autumn budget, the chancellor Rachel Reeves capped the Agricultural Property Relief at £1m, with anything over that being taxed at 20%, half the normal rate of inheritance tax.

The government insists the majority of farms in Northern Ireland will be unaffected.

The change will be introduced from April 2026.

The government is adamant that its policy will not change. Other reliefs may help reduce the amount owed, but concern remains high.

Speaking from Fairview dairy farm near Bangor, the Conservative Party leader said: “We want farmers to know that we are with you, we understand.

“Taxing those assets to force farmers to often give up their land and their children or their grandchildren to not continue in this way of life, I believe, is immoral.

“We are doing everything we can to fight the family farms tax.”

Badenoch also added that “every possible lever” should be used to remove paramilitary groups and “negative criminal activity from the communities who are suffering”.

In a joint move, London and Dublin are to appoint an independent expert to assess whether there is merit in beginning a process which could bring about the disbandment of paramilitary groups.

It followed a recommendation from the Independent Reporting Commission (IRC) which was set up to monitor paramilitary activity.

Northern Ireland Secretary Hilary Benn has insisted paramilitaries will not be paid by the government to “disband”.

He defended the government’s decision to explore the possibility of formal engagement with paramilitary groups.

Badenoch said: “We looked at this proposal when we were in government.

“We didn’t bring it forward because one of the things we must remember is there is no space for paramilitary organisations.

“We need to make sure that they are not benefitting from the harm they cause to communities all over Northern Ireland,” she added.

In her first major speech on foreign policy, Badenoch said if the European Convention on Human Rights (ECHR) continued to stop the government acting in the country’s national interest, the UK would “probably have to leave” the treaty.

Speaking during a key week for international diplomacy, she also called for Prime Minister Sir Keir Starmer to boost defence spending by pulling funds from development aid, welfare and scrapping the Chagos deal.

It comes as US President Donald Trump has been putting pressure on European leaders to increase defence spending.

Responding to journalists’ questions after her speech at an event hosted by the Policy Exchange think tank, Badenoch said: “I have always been very clear that the ECHR should not stop us doing what is right for the people of this country and what is in our national interest, and if it continues to do so at some point we will probably have to leave.

“What I have not agreed with is deciding we should leave without having a plan for what that looks like and how to do so in a way that makes sense.”

Setting out how rules were critical for a trading nation like the UK, she added: “But other countries are breaking the rules and we need to get serious about that and not pretend that those things aren’t happening and that’s really what I want us to focus on.”

Badenoch was speaking the day after a series of international events to mark the third anniversary of Russia’s invasion of Ukraine.

Trump has demanded Nato allies raise defence spending to 5% of GDP and opened talks with Russia, excluding Ukraine, on ending Putin’s war.

Meanwhile, there has been a deepening rift between Trump and Ukrainian President Volodymyr Zelensky, with the US President falsely suggesting Ukraine started the war and branding Zelensky a “dictator”.

Badenoch urged the PM to go further than her party’s previous pledge to spend 2.5% of GDP on defence by 2030, saying this was “no longer sufficient”.

She said cutting international aid could take that total to 3%, and called on the government to find further savings on the welfare bill, as well as by ditching the multi-billion pound Chagos deal.

“There will be painful decisions on government spending,” she said.

“Any country that spends more interest on its debt than on defence, as the UK does today, is destined for weakness.”

On Thursday, Sir Keir will visit the White House and signal a shift in the government’s approach to bringing about peace, including stepping up UK military support and taking a bigger role in Europe’s security.

Sir Keir will be making the case for Ukraine’s direct involvement in any peace talks, warning that an insecure settlement without security guarantees for Kyiv could embolden Russia to attack again.

Badenoch raised her concerns that the world may be seeing “a return to the world of the strong and the weak” with the threat from “a new axis of authoritarian powers” including Russia, China and Iran.

On Trump’s negotiations with Putin, she said: “The danger is that aggression does not simply go unpunished but ends up being rewarded.”

She also reiterated her position that international courts are being used by charities and other organisations “to advance an activist political agenda”.

The ECHR was established in 1950 and sets out the rights and freedoms people are entitled to in the 46 signatory countries.

The treaty is a central part of UK human rights law and has been used to halt attempts to deport migrants who are deemed to be in the UK illegally.

The treaty was also recently cited in a case that allowed a Palestinian family the right to live in the UK, after they originally applied through a scheme designed for Ukrainians.

During the Conservative leadership election, Badenoch said leaving the treaty would not be a “silver bullet” to tackling immigration but last week said her party would review the ECHR and Human Rights Act.

Responding to the speech, a Labour spokesperson said: “If Kemi Badenoch was really the ‘realist’ she says she is, she’d be apologising to the British people for the damage she and her party did to our country.

“Kemi Badenoch was part of a Conservative government which hollowed out our armed forces, made us more reliant on Putin for our energy needs and diminished Britain’s standing on the world stage.”

At Prime Minister’s Questions, the Conservative leader argued that the government’s Schools Bill would cut pay for teachers in academies, close down routes into teaching and block failing schools from automatically becoming academies.

Sir Keir Starmer said academies had been introduced by the previous Labour government and were “here to stay”.

He said it was a “disgrace” that Tory MPs opposed the bill, which also aims to protect vulnerable children, set up breakfast clubs and limit uniform costs.

The Children’s Wellbeing and Schools Bill is a wide-ranging bill which includes measures to create a register of children who are not in school and allow local authorities to intervene if a child’s home environment is assessed as unsuitable or unsafe.

However, it is the changes to academies’ freedoms which have come under most political scrutiny.

Badenoch used all six of her questions at PMQs to ask about the bill.

She argued that academies – first introduced in the late 2000s – had led to improved performances by children in England, adding “poor children in England now do better than wealthier children in Wales”.

She told MPs the government’s changes were “wrecking a cross-party consensus that lasted for decades”.

“Teachers and parents will be horrified at just how bad this bill is. Even his own MPs may not realise it, but the bill will cut teachers’ pay.”

Sir Keir replied that it was important for schools to have flexibility on pay and that the government had introduced an amendment to the bill “to achieve that aim”.

Currently, academies, which are independent of local authorities, have the power to decide how much to spend on teachers’ salaries.

The original wording of the bill would have changed this but for the last few weeks Education Secretary Bridget Phillipson has repeated the line “there will be a floor, no ceiling” on pay.

On Tuesday evening, the government agreed to amend the wording in the bill. Instead, academies will have to have “due regard” to the national pay agreements.

Following PMQs, a Downing Street spokesman said the amendment to the bill was “a sensible step to clarify our ambition for teachers’ pay and conditions”.

“The amendment makes very clear the government’s intention to set a floor on pay but no ceiling so that all state school teachers can rely on the core pay offer,” he added.

The Confederation of School Trusts welcomed the changes – but said there were still parts of the bill that concerned them, including restrictions on bringing people with specialist subject knowledge (but not a specific formal teaching qualification) into the classroom.

Badenoch told the Commons that the bill implies “doctors are not sufficiently qualified to teach biology, that Olympic medallists can not teach PE”, and asked why the prime minister was closing routes into teaching.

“She knows that’s not right,” Sir Keir replied but added that it “should not be extraordinary” to suggest that teachers in schools should be qualified.

Badenoch also criticised the bill for removing a guarantee that failing schools would automatically be turned into academies.

“It is an attack on excellence. It is an attack on higher standards. It is an attack on aspiration,” she said.

Sir Keir said his government was committed to academies and repeated his attack on Conservative MPs for voting against a bill which included “vital protections for children”.

“The bill benefits children who need the nourishment of a breakfast club, the bill benefits the families that can’t afford uniforms, the bill benefits the children who are currently out of school and nobody knows where they are, the bill benefits the children who could be taken out of school by abusers if this bill doesn’t go through.”

He said the opposition leader should “change her mind” and back the measures.

The subject of academies is one where the Conservatives are united and keen to defend their record, with one shadow cabinet minister telling the BBC: “It’s one of the few clear success stories we have to tell.”

Academy schools were first introduced under Sir Tony Blair and enthusiastically expanded by the Conservatives when they came to power in 2010.

So far only one Labour MP – Siobhain McDonagh – has publicly criticised the bill, however it is privately causing significant anxiety among Labour MPs, generally on the right of the party, who are proud of academies.

These are predominantly MPs who are loyal to the government anyway and would not vote against this legislation, which is expected to become law by spring.