Britain will not give in to “voices of weakness” that would “give Putin a veto over our help for Ukraine”, a senior minister has said.

Speaking at a Nato conference on Monday, Cabinet Office minister Pat McFadden warned that Russia had “stepped up” its cyber attacks against Ukraine and its allies over the past year.

But he insisted the UK would not be deterred from supporting Kyiv in its fight against Russia’s invasion.

My message to members today is clear: While no-one should underestimate the Russian aggressive and reckless cyber threat to Nato, we will not be intimidated by it and we will never allow it to dictate our decisions or policies

He said: “We will not join those voices of weakness who want to give Putin a veto over our help for Ukraine.

“And given the scale of Russia’s hostility, my message to members today is clear: While no-one should underestimate the Russian aggressive and reckless cyber threat to Nato, we will not be intimidated by it and we will never allow it to dictate our decisions or policies.”

His comments at Nato’s cyber defence conference in London follow not just an increase in Russian cyber attacks, but a change in Moscow’s policies that lowered the threshold for using nuclear weapons.

Claiming that the Ukraine war was becoming a “global” conflict, Russian president Vladimir Putin said he was entitled to target the military facilities of countries that had supplied weapons to Kyiv.

The change represents a significant escalation in tensions between Russia and the West, following US president Joe Biden’s decision to give Ukraine permission to use American-supplied long-range missiles to attack targets within Russia itself.

Mr McFadden, whose brief as Chancellor of the Duchy of Lancaster includes national security, went on to say Russian cyber attacks could “turn off the lights for millions of people” and accused Moscow of targeting British media, telecoms and energy infrastructure.

He added: “Aided by allies including the UK, Ukraine has had to defend itself from crippling Russian cyber attacks on its electricity grid, its airports, and other critical national infrastructure.

“Russia has targeted its mobile networks – cutting off communications for millions at a time – and on occasion, disabled the air raid warning system in Kyiv.”

Mr McFadden also used his speech to announce a new Laboratory for AI Security Research (LAISR) aimed at helping the UK stay ahead in “the new AI arms race”.

In a few days, I and the UK’s senior national security officials will be sitting down with British businesses to discuss how they can boost their own security and help defend the nation from actors with malign intent - particularly from Russia

The centre will bring together GCHQ, Oxford University, the National Cyber Security Centre, the Alan Turing Institute and numerous Government departments, and be backed by an initial £8.2 million in state funding.

He added that the UK would look to strengthen Nato’s “collective cybersecurity” through a new “incident response project” to help deal with attacks on critical national infrastructure, while also boosting Britain’s own defences.

He said: “In a few days, I and the UK’s senior national security officials will be sitting down with British businesses to discuss how they can boost their own security and help defend the nation from actors with malign intent – particularly from Russia.

“And I’ll be very clear with them: Russia won’t think twice about targeting British businesses in pursuit of its goals. It is happy to exploit any gap in our physical or cyber defences.

“And so I urge them to do everything in their power to strengthen their own security and protect themselves, the country and our allies from this threat.”