Vladimir Putin is "highly unlikely" to use nuclear weapons in his war with Ukraine but has shown himself to be "totally irrational", the Defence Secretary Ben Wallace has said. It comes as Mr Wallace prepares to join a crisis meeting of European nations following a series of explosions that caused major damage to Russia's undersea Nord Stream pipelines.

The Russian president has threatened to use "all the means at our disposal" if his country is threatened, seen as a sign that he could use tactical nuclear weapons in response to attacks on parts of Ukraine he has annexed. But Mr Wallace played down the prospect, telling a fringe meeting at the Tory party conference that although the use of nuclear weapons was in the Russian military doctrine, it would be unacceptable to Moscow’s allies India and China.

He said Mr Putin "was given a very clear sense what is acceptable and unacceptable" in meetings with the Indian and Chinese leaderships. But Mr Wallace added that the Russian leader’s actions, from the nerve agent attack in Salisbury to the invasion of Ukraine, were "totally irrational".

In a sign of the latest concerns about Russia’s actions, Mr Wallace will join the crisis meeting of northern European nations on Monday to discuss the security of pipelines and undersea cables. Prime Minister Liz Truss has said the explosions which damaged the Nord Stream pipelines were "clearly an act of sabotage".

Mr Wallace said the UK and the Nordic nations were "deeply vulnerable" to acts of sabotage against cables and pipelines.

"I’ll be convening, with the Dutch, a virtual joint expeditionary force meeting on Monday," he said. "So I have to break my timetable tomorrow to meet 10 of the Nordic states about what we’re going to do about it because the Nordic states and ourselves are deeply vulnerable to people doing things on our cables and our pipelines.

"So suddenly, that becomes a big issue we have to get to the bottom of. We have to think about what assets we can move to give people reassurance or, indeed, investigate what’s going on."

Mr Wallace said the prolonged war in Ukraine had shown the need to make sure stockpiles of equipment and supply chains were protected, as he admitted some supplies were running "fairly low". Defence spending had been "hollowed out" over 30 to 40 years so "unsexy parts" of the budget had been neglected, he said.

Mr Wallace acknowledged that "some of our weapons stockpiles are fairly low and the supply chains switched off 10 years ago, so we have to reinvigorate that". He said the Russians were suffering badly, in part because some of their suppliers were in Ukraine and had been bombed – a sign of the "strategic genius that President Putin is clearly proving to be".