Europe needs to acquire nearly a thousand more nuclear warheads if it hopes to deter Vladimir Putin, a German political scientist has warned.

Maximilian Terhalle, a visiting fellow at Stanford University’s Hoover Institution, said Putin had at least 1,550 long-range nuclear missiles, while Europe had only several hundred.

Concerns that President Donald Trump could scale back security guarantees in Europe has led to discussions in EU capitals about a nuclear deterrent that is independent of the United States.

“Trump has turned an enemy, Russia, into a friend, and that’s something of grievous concern. In the case that America draws away from Europe entirely – not yet – we have to ask how we will compensate for that because Russia’s imperial ambition has not diminished at all,” Dr Terhalle told The Telegraph.

“We need to be on par with Russia’s 1,550 strategic warheads, otherwise we will not strategically influence what is going on in Putin’s mind, which is critical for deterrence. Add to that, Russia has an unhelpful 10:1 lead as far as short-range tactical nuclear weapons are concerned,” he added.

Dr Terhalle said France and Britain’s nuclear arsenal combined consisted of around 450 long-range “strategic” nuclear warheads, meaning weapons that would determine the outcome of a war, and 200 smaller “tactical” warheads.

“I’m a staunch transatlanticist, as such I don’t want to see Nato breaking up by any means, but we also need to look out for ourselves,” he added.