JOE HAINES: At best, Corbyn is guilty of such naivety he shouldn't be allowed out without a nanny

Jeremy Corbyn is not a Kim Philby, a Donald Maclean or a Guy Burgess. I say that as one of the most anti-Corbyn voices you will find anywhere.

But unlike the Cambridge Three, he knew nothing that would be immediately useful to an enemy power when the Czechs approached him, and he knows little more now that he is a Privy Councillor.

The KGB, who controlled the diplomat/spies at the satellite Soviet embassies in London, especially the Czechoslovaks and the Bulgarians, realised that. When they courted Labour MPs, it was for their potential, not for their information.

What Corbyn is guilty of, at least, is such astonishing naivety that he shouldn't be allowed out without a nanny.

Why does he think they approached him in the first place? For two decades after he was elected to Parliament in 1983, Corbyn was regarded as the lightest of lightweights. To some of us he still is.

Why did he think the East Germans, whose Stasi secret service was second only to the KGB in its efficiency and ruthlessness, allowed him to take a motorbike holiday through their country with his then girlfriend, Diane Abbott, on his pillion?

Jeremy Corbyn (pictured) knew nothing that would be immediately useful to an enemy power when the Czechs approached him, writes Joe Haines

Jeremy Corbyn (pictured) knew nothing that would be immediately useful to an enemy power when the Czechs approached him, writes Joe Haines

Did he never realise that the Stasi and the Czech intelligence services would be opening files on him?

Of course, he dismisses the stories about him as bizarre, the absurd work of a fantasist. Last night he even released a video — on social media, naturally — in which he cynically accused the Right-wing media of going 'a little bit James Bond', and dismissed the allegations as 'ridiculous smears'. To borrow the celebrated retort of Mandy Rice-Davies: well, he would say that, wouldn't he?

The truth is that if the Czechs did not pursue their relationship with Corbyn —who says he thought his contacts were diplomats, not spies, which was a distinction without a difference — it was because they thought he didn't have any potential.

It was a mistake anyone could make. After all, not even Corbyn himself would have been lunatic enough to imagine he might ever become Prime Minister, or even the Leader of the Opposition. The same goes for John McDonnell. No one ever contemplated that one day he would be a potential Chancellor of the Exchequer.

One of the first problems Corbyn would face if he ever reached No. 10 would be the file on McDonnell presented to him by MI5. The next would be the file on former Guardian journalist Seumas Milne, now Corbyn's all-powerful, Marxist-sympathising communications chief.

And after that, the files on the senior members of his present staff, including several ex-communists.

The advice on all of them would be unanimous: don't employ them in your Government. They were and are defenders of the Soviet Union.

If they were in positions of power in a British Government, then intelligence co-operation with the United States would be non-existent. The Americans wouldn't trust them with the time of day.

Who could blame them?

At the end of World War II, when Winston Churchill suffered a shock defeat by Clem Attlee in the 1945 General Election, the Soviet secret police cast their net wide in Britain in the search for information.

It was not just politicians — journalists and trades union officials were also paid informants. Two of Britain's leading industrial correspondents reported to Moscow regularly on the internal affairs of the Labour Party in the Seventies.

That I know for certain. Others were suspected.

The lobby correspondent of the Daily Worker, the British Communist Party's newspaper (later The Morning Star), and one-time chairman of the parliamentary lobby, Peter Zinkin, was a Soviet agent. That I heard from the highest possible source in the Foreign Office.

I knew Zinkin well and frequently lunched with him at The Gay Hussar, the favourite restaurant of Left-wing journalists. He would try to pump me about Britain's relations with Israel, which was his particular remit.

He didn't know that I knew what he was. He learned nothing. I regarded him as the contact point for the many Left-wing Labour MPs who enjoyed the 'hospitality' of the Soviet and satellite secret services. Slowly the facts are dribbling out — witness Ken Livingstone's admission yesterday that he spent ten days in Russia at the expense of the KGB. Livingstone is many things, but naïve he is not.

(He denies giving any information to a spy who posed as a journalist. He says he thinks they were 'sounding him out' in case he got into a position of power.)

They approached civil servants, too. One day, one of my junior staff at No. 10, came into my office and told me he was having lunch with an attache from the Bulgarian embassy. I exploded. My staff were under strict instructions to tell me in advance of their luncheon engagements, which meant I could veto them.

I consulted the security officer at No. 10. He thought, in terms of protocol, it was too late to cancel the lunch, so I told the junior staff member he could go ahead with it, but warned him severely about what he said and did.

Theresa May (pictured) was right this week to call for open and transparent statements from the Labour leader

Theresa May (pictured) was right this week to call for open and transparent statements from the Labour leader

He came back late from his lunch, over-confident as ever, and told me the attache had been perfectly nice — and had even given him a case of wine. In the Bulgarian embassy.

I exploded again. 'Don't you realise,' I asked, 'that you would have been filmed accepting it?'

No, he didn't.

I confiscated the wine.

Following the unexpected Labour victory in 1945, the News Editor of the Daily Worker crowed that the Communist party had eight 'cryptos' [informants] among the huge influx of new Labour MPs.

Prime Minister Attlee was well aware of the cryptos.

He instructed the powerful general secretary of the party, Morgan Phillips, to draw up a list of those not to be trusted. Morgan did so. He headed the list 'The Lost Sheep'.

In 1948, Attlee sent four of the lost sheep to the political slaughterhouse and expelled them from the party: John Platts-Mills, Leslie Solley, Konni Zilliacus, Hugh Lester Hutchinson, though for some inexplicable reason Zilliacus was allowed back into the party and Parliament a few years later.

He was in receipt of a monthly payment from the Soviets.

Most of the Soviet agents or 'useful idiots' — as Lenin is said to have called those willing to do the Soviets' work without payment — are now dead, but any still alive who visited the Communist Party's headquarters in King Street in London's West End between 1945 and 1970 have good reason to shiver today as old memories are revived.

Anyone at Westminster, in the trades unions and in political journalism between the Sixties and the Eighties who didn't know what the communist secret services were up to was wilfully blind.

They tried to rope in anyone who might be a potential help to their cause.

The unions, in fact, were a better target for the KGB than the Labour Left-wing. It was the unions that had real power.

That's why Jack Jones, the most powerful trade unionist of his day and leader of the Transport and General Workers' Union, was on their agent list. They paid Jones.

When I discovered this in Christopher Andrew's masterly official biography of MI5 and reported it in the traditional Left-wing magazine, Tribune, I was roundly abused by two Labour MPs, one of them the eccentric Tam Dalyell.

When I, in turn, rounded on him, he apologised and admitted that he hadn't read the book. It was just a knee-jerk reaction to one of their heroes being shown to have feet of red clay.

There were other useful idiots in the union movement, including at least one member of Labour's National Executive Committee as well as openly admitted communists. There still are to this day.

The lure of the Soviet and post-Soviet ideology was and is strong. Trotsky and Marx are still idols to many on the left. More than that — they are their guiding lights.

Marx is what moves John McDonnell. I suspect Corbyn is more a Trotsky man.

Theresa May was right this week to call for open and transparent statements from the Labour leader. I doubt if they will come.

What we will get is a steady trickle of new names and old information. And denials, of course.

When they come, remember Mandy Rice-Davies.