I wish I smoked cigars. You can’t have a proper right-wing conspiracy without cigars. You also need a homophobic policeman, a posh casino, very large brandy glasses and silky evening suits. It helps if you are all Freemasons, too. With the props assembled it’s time to frustrate Helen Mirren or Juliet Stevenson in their lone fight for justice, a fight for which they have been prepared to sacrifice love and companionship.

Absurd stereotypes abound in television drama. So do improbable plot lines. In a recent episode of ER, a surgeon with only one arm operates on a pig, having had his other arm chopped off by a helicopter blade while evacuating a patient from his hospital when it was threatened by a smallpox outbreak.

Such idiocies do not exactly enhance one’s viewing pleasure, but they are broadly acceptable when all that is on the screen is an unashamed work of fiction. Cambridge Spies, the BBC’s new multimillion pound drama about the career of the spies Burgess, Philby, Maclean and Blunt, purports to be something rather different. And it must be judged by a different standard.

If Cambridge Spies were a pure work of fantasy, it would be thought rather insipid. Complex characters are introduced without their complexities being explored in any detail and important moral issues are glossed over. I very much doubt that as a fictional tale the script would have made it on to the stage of a fringe theatre, let alone be used for such a prestige series. What gives this programme its savour and inspired the BBC to part with so much money is its claim to be very largely factual, a portrayal of extraordinary events that really happened.

So the fact that every episode begins with the disclaimer that “certain events and characters have been created or changed for dramatic effect” poses more questions than it answers. It leaves the viewer unsure in each scene whether they are watching a real event or something that the author made up. This is made far worse by the obvious desire to make the protaganists appear to be sympathetic figures. What has been added to their stories, and what omitted, to achieve this effect? And how can the viewer judge whether the characters were really worthy of the response the programme prompts us to give?

I haven’t much to go on, but let me take a wild guess. Kim Philby and Guy Burgess did not meet for the first time when a Nazi student called Philby a “Jew lover” for chatting up a Jewish girl. Two toffee-nosed academics did not talk quietly in a dark corner about turning a blind eye to Hitler and Mussolini and one of them did not turn to the other and say “we must let them behave badly to the Jews”. Burgess did not have a conversation in which his Cambridge tutor said: “The right people are in charge. Us. And us and them don’t mix.”

And Philby did not turn to his Austrian girlfriend and say “I went to a very fine public school and Trinity College, Cambridge, my back is straight and my top lip is stiff and I have a British passport” before persuading a Viennese guard to let them through a checkpoint . . . Just guessing.

In places, and not just the ones I’ve quoted, Cambridge Spies is simply risible. When the Nazis invaded the Soviet Union and the Russians changed sides, the four spies found themselves briefly working for an ally. It is vital that we all understand how happy they are about this. Guy Burgess is therefore shown literally skipping down the street whistling a merry tune. A burst of the Hallelujah Chorus follows. Burgess wasn’t the only one with a smile on his face. I was laughing out loud.

I didn’t laugh long, however, for the bits of Cambridge Spies that aren’t funny are simply offensive.

There is nothing wrong with portraying the spies as believing in their own sincerity. When John Travolta said he intended to play the Bill Clinton character in Primary Colors with “a valentine in my heart”, right-wing critics were scathing. Yet understanding that Clinton loves himself is vital to playing him. The same is probably true of Philby and Maclean, though perhaps not the others.

It is also true that being a spy, even one who causes as many deaths as these characters did, does not make you inherently evil. Helping to undermine a brutal dictatorship by feeding information to a democratic government is a laudable, brave activity. The problem with the Cambridge spies is that they were doing the opposite. And they had every reason to know that they were doing so.

The examination of ideas in this programme is remarkably shallow. In Indiana Jones and the Last Crusade Harrison Ford shoots a number of German soldiers and then turns to Sean Connery and says: “Nazis. I hate those guys.” Intellectually Cambridge Spies rarely rises above this level. It turns out that one of the characters changed for dramatic effect was Stalin.

Communism was and remains a pernicious, totalitarian doctrine, producing pernicious, totalitarian results. To see the BBC whitewashing people who contributed to the murder of millions by their treachery is nauseating. Enjoy your prime time drama everybody.

Cambridge Spies, Friday, BBC Two, 9pm

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