AS pressure mounts on Labour leader Jeremy Corbyn to authorise the release of Cold War files relating to his activities in the 1970s and 80s, it will be interesting to see how he and his political comrades respond.

Along with Ken Livingstone and shadow chancellor John McDonnell, Mr Corbyn is implicated in claims about Labour MPs’ connections with Cold War agents, after one such agent – Czechoslovak Jan Sarkocy, who was based in London during the 1980s – has said that Labour MPs were paid up to £10,000 for secret meetings with spies during this most diplomatically febrile period of modern history.

Sarkocy, who was thrown out of Britain by Margaret Thatcher’s government, claims he was treated to a “farewell party” near the Ministry of Defence by his Labour informants, a party which, if it did indeed take place, must have been a curious – and possibly rather dull – affair, to say the least.

More seriously, Mr Sarkocy also claims both Mr Corbyn and Mr Livingstone were paid cash for information, and were “good sources”, while Mr McDonnell, he says, was regularly meeting a KGB agent.

Messrs Corbyn and McDonnell deny the claims (as does former London mayor Mr Livingstone), each dismissing the retired agent, who now lives in Slovakia, as a “fantasist”.

Oh, that’s all right then.

But, of course, it is far from all right.

The two most high-profile men at the centre of these claims aspire to be our next prime minister and chancellor – and yet they seem to believe they can brush off this potential scandal with ease.

One assumes that, given their respective positions, one or both of them will shortly be launching libel actions against The Sun newspaper, which broke the story.

After all, these are serious claims which suggest that serving MPs were acting against the interests of their own nation by having dealings with known enemies of the state.

Small wonder that calls are growing for Mr Corbyn in particular to be open about his links to former Cold War spies – and the easiest way for him to do this is to authorise the release of files kept on him by the notorious Stasi during this period, files understood to have been compiled when Mr Corbyn took his then girlfriend Diane Abbott on a motorcycling holiday in East Germany.

While younger observers may shrug and dismiss all this as ancient history and the stuff of old “the grey goose flies at dawn” spy novels, the Cold War is part of recent history; and, as such, currently prominent politicians’ actions during this time must be subject to proper and rigorous scrutiny.

As defence minister Tobias Ellwood pointed out this week, Mr Sarkocy’s claims raise “legitimate concerns” about Mr Corbyn’s patriotism.

If Mr Corbyn and his fellow MPs have behaved in a way which benefited our enemies at the time, then surely it is right that such actions be explained.

After all, if Mr Corbyn were to become our next prime minister, he would be responsible for the defence of the nation and privy to security information at the absolute highest level.

It is a moot point what our security services would make of giving top level clearance to a prime minister with such questions hanging over his head.

That is why Mr Corbyn must authorise the release of his Stasi file (and how bizarre is it to be saying that about a putative prime minister of this country?) and co-operate in any parliamentary investigation which may arise from Mr Sarkocy’s claims.

Dismissing the former agent as a “fantasist” simply will not wash; and both Mr Corbyn and Mr McDonnell must submit themselves to proper scrunity should a parliamentary inquiry be set up.

Mr Corbyn has never denied knowing Mr Sarkocy – any more than he has denied knowing IRA terrorists or his Hamas and Hezbollah “friends” – but a spokesman for him insisted this week that “Cold War Czechoslovak spy Jan Sarkocy is a fantasist whose claims are entirely false and becoming more absurd by the day. These claims are ridiculous smears.”

That may well be the case – which is why Mr Corbyn should surely wish to prove it to be so.

He can do this first by acting transparently and agreeing to the release of his Stasi file, which is archived in Germany.

He can do it secondly by co-operating fully with the parliamentary cross-party foreign affairs select committee – and by appearing before it to answer the many legitimate questions which this affair raises about the man who would be our next prime minister.