The TV series Friends undermined family values; Sesame Street taught ethnic minorities about civil disobedience; Happy Days had a subtle anti-Vietnam subtext; and the 1980s cop show MacGyver tried to persuade pistol-packing Americans that guns are bad.

That is the considered opinion of Ben Shapiro, an investigative author and right-wing columnist who will publish a detailed expose tomorrow telling how Hollywood producers, writers and actors have been secretly using TV to promote what he calls a "radical" left-leaning political agenda.

Shapiro's book, Primetime Propaganda revolves around comments by 70-odd industry heavyweights he approached for interviews.

The book promises to "profile the biggest names in showbusiness over the past 50 years" and includes a series of "gotcha" moments, in which the architects of the best-watched TV shows of modern times tell how they tried to use the medium of broadcasting to, as Shapiro puts it, "shape America in their own leftist image".

"I was shocked by the openness of the Hollywood crowd when it came to admitting anti-conservative discrimination inside the industry," Shapiro said. "They weren't ashamed of it. In fact, some were actually proud of it."

The book's contents will only add weight to allegations - often aired by conservative Americans - that Hollywood is the exclusive domain of leftie propagandists.

Among Shapiro's most revelatory interviewees is Marta Kauffman, the co-creator of Friends, who recalls how she hired a "bunch of liberals" to run the programme to "put out there what we believe".

In 1999, she admitted casting the actress sister of Newt Gingrich, the prominent Republican, to play a preacher at a lesbian wedding because she wanted to annoy conservatives.

"When we did the lesbian wedding, we knew there was going to be some flak," said Kauffman. "I have to say, when we cast Candice Gingrich as the minister of that wedding, there was a bit of a 'f*** you' in it to the right-wing, directly."

Elsewhere in the book, Vin DiBona, the producer of MacGyver, agrees that Hollywood has a liberal bias, saying "I'm happy about it, actually." The cult cop show advanced an anti-gun agenda, he added. "That was the whole premise of the programme, that MacGyver used his brain power and skill and science, and solved all the difficulties through ingenuity. No guns, no knives."

Not just a comedy about military camaraderie, M*A*S*H also had a pacifist agenda, the show's co-creator and director Gene Reynolds told Shapiro, who said: "We wanted to point out the wastefulness of war."

And, with regard to Happy Days, writer Bill Bickley said he "had a whole subtext" attacking the Vietnam War. "If you really look for it, you can find it."

The book is perhaps at its most condemnatory when accusing the creators of Sesame Street of attempting to brainwash young children. It quotes Mike Dann, one of the show's founding executives, saying it "was not made for the sophisticated or the middle class".

Early episodes featured the character Grover breaking bread with a hippie. Oscar, who lived in a rubbish bin, was supposed to address "conflicts arising from racial and ethnic diversity".

"Sesame Street tried to tackle divorce, tackled 'peaceful conflict resolution' in the aftermath of 9/11 and had [gay actor] Neil Patrick Harris on the show playing the subtly named 'fairy shoeperson'," notes Shapiro.

As to whether there may be a touch of McCarthy-esque paranoia about his belief that film-makers are planting the seed of socialism in the bosom of America, he adds: "It's not paranoid to speak the truth. Hollywoodites admit openly to messaging their product, and to their scorn for conservative Americans. I'm just reporting what they told me."

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