Vladimir Putin’s hopes of a diminished Nato have been proved “completely wrong” by Sweden and Finland joining the alliance, Boris Johnson said.

The two Nordic countries are on track to end their historic neutrality and join the defence alliance after Turkey withdrew its objections.

Arriving at a summit of Nato leaders in Madrid, where he will commit extra UK forces to the alliance’s effort to protect its eastern flank, the Prime Minister said Russian President Mr Putin is getting “more Nato”, not less, as a result of his actions in Ukraine.

The UK already has a significant military presence in Estonia and the Prime Minister will use the summit to expand its headquarters in the Baltic nation.

Officials said this will ensure the UK can provide rapid reinforcements if needed, and deploy artillery, air defence and helicopters.

(PA Graphics)(PA Graphics)

The alliance plans to have 300,000 troops at high readiness – up from the current 40,000 – and the UK will commit capabilities in land, air and sea to the “new force model”.

Mr Johnson said: “The first lesson really from today is that if Vladimir Putin was hoping he would be getting less Nato on his western front as a result of his unprovoked, illegal invasion of Ukraine, he’s been proved completely wrong – he’s getting more Nato.

“This is a historic summit in many ways, but we’ve already got two new members coming in, Finland and Sweden, a huge step forward for our alliance.

“And what we’re going to be doing now is talking about what more we can do as an alliance to support the Ukrainians but what we also need to do to make sure that we think about the lessons of the last few months and the need for Nato to revise its posture on its eastern flank.”

The Prime Minister will call on alliance leaders to increase their defence budgets, but he is under pressure to do more on the UK’s military spending.

Boris Johnson surrounded by journalistsPrime Minister Boris Johnson talks to journalists on his plane from Germany to the Nato summit in Madrid (Stefan Rousseau/PA)

Defence Secretary Ben Wallace, who is also attending the Madrid summit, said that while he has enough funding for the “here and now”, extra investment is needed in the next Government spending round from the middle of the decade.

“My (spending) settlement was done before Russia invaded Ukraine. Russia is very, very dangerous on the world stage,” he told Sky News.

“The world is less secure than it was two, three years ago, and is not looking likely to change for the rest of the decade.

“That is the moment, in the middle of the decade, to say we should commit to increased funding.”

Downing Street defended the Government’s record on funding, insisting the benefits of new technology and kit outweighed cuts in the number of soldiers.

The row comes after the Chief of the General Staff, General Sir Patrick Sanders, warned any further cuts to the size of the British Army would be “perverse”.

The Prime Minister’s official spokesman said: “We are still of the view that we have set out with this massive increase in defence funding is the right one because it would be wrong – given what we are seeing play out in front of our eyes – to focus solely on numbers when we can see the impact that the latest technologies, equipment, training, intelligence are having.

“We are confident that we can do both, essentially, with this £24 billion extra that is going in to our armed forces.”

As well as paving the way for Sweden and Finland to join, the Madrid summit will focus on the alliance’s future in response to Russia’s invasion of Ukraine and the emergence of China as a military power.

US President Joe Biden said two additional F-35 fighter jet squadrons will be sent to the UK, while a new permanent headquarters will be set up in Poland as part of his commitment to the alliance.

“Today I’m announcing the United States will enhance our force posture in Europe and respond to the changing security environment as well as strengthening our collective security,” he said.

Nato secretary-general Jens Stoltenberg said: “We will agree a fundamental shift to our deterrence and defence.

“With more forward deployed combat formations. With more high-readiness forces. And also with more pre-positioned equipment.

“This is the biggest overhaul our collective defence since the end of the Cold War that will be agreed at this summit.”

The alliance’s new strategic concept replaces one drawn up in 2010, when relations with the Kremlin were warmer and Russia was a “strategic partner”.

The Nato chief said: “I expect that, when leaders agree the strategic concept today, they will state clearly that Russia poses a direct threat to our security.”

He said the allies will also agree that China “is a challenge to our values, to our interests and to our security”.

“China is not an adversary but, of course, we need to take into account the consequences to our security when we see China investing heavily in new modern military capabilities, long range missiles, nuclear weapons, and also trying to control critical infrastructure, for instance, 5G networks in our own countries,” he said.

Foreign Secretary Liz Truss used an appearance at the summit event to warn that “with China extending its influence through economic coercion and building a capable military there is a real risk that they draw the wrong idea which results in a catastrophic miscalculation such as invading Taiwan”.

She said: “That is exactly what we saw in the case of Ukraine, a strategic miscalculation by Putin, so this is why it’s so important that the free world work together to help ensure that Taiwan is able to defend itself and to stress the importance of peace and stability across the Taiwan Strait.”