The UK has been "fooled" into believing international law alone can keep global peace, according to Conservative leader Kemi Badenoch.

In a speech on Tuesday, Badenoch will say the UK should "review" its foreign policy strategy and put British interests first.

Badenoch hinted last week that she may advocate for pulling the UK out of the European Convention of Human Rights (ECHR).

She will be making her speech during a key week for international diplomacy, with both Prime Minister Sir Keir Starmer and French President Emmanuel Macron travelling to the White House to discuss the war in Ukraine and smooth relations with the Trump administration.

Badenoch will say on Tuesday that "the world has changed", leaving the UK "not ready" to deal with modern crises.

The Conservative leader will argue the UK must also change and act in its national interest by protecting "its borders, its values and its people".

"Strengthening Britain must be the principal objective at the heart of everything we do," she will say.

"We have let ourselves be fooled into believing that international law alone can keep the peace" when "faced with a regime with no respect for the law".

Her speech will be delivered a day after a series of international events to mark the third anniversary of Russia's invasion of Ukraine.

Discussions around peace talks have rapidly evolved over the past week after US President Donald Trump opened negotiations with Russia, in a meeting which excluded Ukraine.

President Trump has said he wants a quick end to the war and has claimed Russian President Vladimir Putin also wants to reach a deal.

Meanwhile, there has been a deepening rift between Trump and Ukrainian President Zelensky.

Zelensky has accused the US president of helping Russia "break out of years of isolation" before Trump turned his ire on the Ukrainian leader, calling him a "dictator" and suggesting his country started the war.

On Thursday, Sir Keir will visit the White House to make 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.

The prime minister also signalled 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.

Trump has been putting pressure on European Nato allies to increase their defence spending.

In her speech, Badenoch will also advocate for further investment in defence and argue the government "must do what it takes to protect Britain".

The Conservatives ran on a manifesto pledge to increase defence spending from 2.3% to 2.5% of GDP by 2030, but in recent days have pressed Labour to go further.

"There will be painful decisions on government spending," Badenoch will say.

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

Badenoch will also reiterate her position that international courts are being used by charities and other organisations "to advance an activist political agenda".

The ECHR 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.

"This Labour government is fixing the Tories' mess and delivering on our Plan for Change, the core foundations of which are economic stability, national security, and border security."