In the week since Russia invaded Ukraine the comparisons between the current situation and the events which led up to the Second World War have frequently been compared.

Ukrainian President Volodymyr Zelensky has invoked the conflict when appealing for help in his country’s fight against Russia.

Others have drawn comparisons directly between today’s leaders and those involved in titanic struggle.

Tobias Ellwood, Tory chairman of the House of Commons Defence Committee, pithily said Boris Johnson’s initial response to the invasion had been “more Chamberlain than Churchill”.

And commentators have lined up to speculate on what Putin does or does not have in common with Hitler.

But where does this get us? Is any of it useful?

Speaking to the BBC, Oxford history Professor Margaret MacMillan said: “I think we like to look back to history and think there’s something there that will give us the key to what is going on today.

“We’re looking back to the 1930s and saying: ‘Is it appeasement? Is it what happened in 1938 when Britain and France and their allies decided to hand over part of Czechoslovakia to Hitler? Or is it more like what happened in 1939 when Hitler created an excuse to attack Poland?’

“And there’s something in that – but the parallels are never very tight and exact.

“Things were different in the 1930s.”

Several things have indeed changed since the 1930s. And not all of them for the better.

For one thing, before the Second World War there were no nuclear weapons.

Now, there are tens of thousands of them.

The most powerful modern nuclear weapons are estimated to be 50 times more damaging than the bomb which flattened Hiroshima in August 1945.

This means the stakes now are much higher than in the late 1930s.

But other things are more similar.

Professor MacMillan explained: “The attempt was then – and I think it’s got to be there today – to try and avoid war.

“What the people who are now accused of appeasement – Neville Chamberlain and [Édouard] Daladier – were doing was trying to achieve a repeat of the First World War.”

This, obviously, was a noble aim. But, Professor MacMillan argued, they had missed several warning signs from inside Germany.

She said: “What they failed to understand – and this is where I think there really is a parallel – is that when Hitler talked about what he wanted to do, they tended to dismiss that as rhetoric.

“And I think we have done that with President Putin.”

Contemporary political voices have also noticed this.

Sir Gerald Howarth, who served as a defence minister between 2010-12 and was also chairman of the all-party parliamentary group on Ukraine in his time as an MP, said: "We didn't think Putin would invade Georgia. We didn't think he'd annex Crimea. We didn't think he would invade Ukraine. He's done all of these things.

“If I were still in a leadership role in the country, I would be erring on the cautious side and positioning the country to prevent there being any miscalculation while making sure that we were prepared.”

The stakes now are infinitely higher than they were in the 1930s.

A serious escalation – thought to be unlikely by experts – could kill millions and radically alter life as we know it.

So, what can we learn from the past to make sure it doesn’t happen?

Professor MacMillan said the past could provide a potential off-ramp.

“It’s very hard to get through to them I think,” she said. “I assume what’s happening now is that people around the world are thinking ‘who can talk to him?’

“One possible avenue might be China and the president of China.

“The Chinese may be able to prevail on him not to go any further but it’s very difficult to stop him.

“Once force is unleashed, then I’m afraid often the only way to stop force is with counter-force.”

Whatever lessons there are to be learned from history, now would be a very good time for the world to study up.