Prime Minister Rishi Sunak promised an extra £75 billion in defence spending over the next six years.
He says it will put the UK arms industry on a “war footing” in the face of threats from an “axis of authoritarian states” including Russia and China.
He said the UK will spend 2.5% of gross domestic product (GDP) on defence by 2030 because the world was “the most dangerous it has been since the end of the Cold War”.
This re-commits to a target set by former prime minister Boris Johnson in 2022 and firms up Mr Sunak’s own stance on the defence budget.
The Prime Minister and Chancellor Jeremy Hunt had previously only said the 2.5% goal would be met when the economic conditions allow.
Mr Sunak and Mr Hunt have come under increasing pressure to boost spending from some Tories, including former prime minister Liz Truss, who has pushed for a 3% commitment at a time when Vladimir Putin’s Russia is waging war on a European neighbour.
Mr Sunak said: “In a world that is the most dangerous it has been since the end of the Cold War, we cannot be complacent.
“As our adversaries align, we must do more to defend our country, our interests and our values.”
Announcing the commitment at a military base in Warsaw, Mr Sunak warned about the threats facing the world from the “axis of authoritarian states with different values to ours”, including Russia, China, Iran and North Korea.
“The danger they pose is not new, but what is new is that these countries or their proxies are causing more instability, more quickly, in more places at once.
“And they’re increasingly acting together, making common cause in an attempt to reshape the world order.”
The commitment to boost defence spending, made alongside Nato secretary general Jens Stoltenberg at a military base in Ukraine-neighbouring Poland, was clearly aimed at encouraging other European allies to follow suit.
Former US president Donald Trump was hugely critical of European Nato members failing to pay their way while he was in the White House, and the prospect of his return could lead to uncertainty about the future of the alliance.
Mr Sunak said: “We cannot keep expecting America to pay any price or bear any burden if we ourselves are unwilling to make greater sacrifices for our own security.”
Mr Stoltenberg said: “The criticism we have heard from the United States, not only from former president Donald Trump but also from others, has not primarily been a criticism against Nato allies.
“It has been a criticism against Nato allies not spending enough on Nato.
“That is changing.”
Drawing lessons from the war in Ukraine, the Government promised a further £10 billion over the next 10 years to ensure the military does not run out of ammunition and missiles.
This represents nearly a doubling of current UK spending on munitions production and will focus on capabilities including air defence missiles, anti-armour munitions and 155mm artillery shells.
Mr Sunak said: “We will put the UK’s own defence industry on a war footing.”
Downing Street suggested that unlike the 2.5% ambition set out by Mr Johnson, the current prime minister had set out a “fully-funded plan” with money for defence coming from cuts to civil service jobs across Whitehall and a shift in research and development budgets towards defence.
The increase in defence spending will also include the commitment to maintain funding for Ukraine at current levels will also contribute to reaching 2.5%, because “the Prime Minister believes that backing Ukraine is backing the UK”, a No 10 spokeswoman said.
Shadow defence secretary John Healey said Labour “wants to see a fully funded plan to reach 2.5% but the Tories have shown time and time again that they cannot be trusted on defence”.
“The British public will judge ministers by what they do not what they say. Since 2010, the Conservatives have wasted more than £15 billion mismanaging defence procurement, shrunk the army to its smallest size since Napoleon, missed their recruitment targets every year, and allowed morale to fall to record lows.”
During his two-day trip to Poland and Germany, Mr Sunak also committed a further £500 million package of military aid to Ukraine.
After talks with new Polish Prime Minister Donald Tusk, Mr Sunak said the UK and Poland “will call on all our partners to look again at what more they can do” to support Kyiv in its fightback against Russia.
“Across Europe, I think Poland and the UK are part of a growing wave of countries that are taking greater responsibility for our collective security,” Mr Sunak said.
He also said the two nations “will strengthen our co-operation” on work on the “crucial issue of air defence” and that RAF Typhoons will be deployed to help police Poland’s skies next year.
Published: by Radio NewsHub