Ricky Tomlinson is currently appealing a conviction from 1973 in the Court of Appeal, along with 14 others.
Royle Family star Ricky was sentenced to two years in prison for picketing building sites in Shrewsbury in 1972.
Tomlinson and his fellow pickets, known as the Shrewsbury 24, were convicted of offences including unlawful assembly and affray.
Six were imprisoned - reports Mirror Online.
Ricky, who was given a two-year sentence and served 18 months in Leicester’s Welford Road jail, is among 14 of the group attempting to overturn their convictions at the Court of Appeal.
Des Warren, who was jailed for three years and died in 2004, was represented by members of his family.
Their cases were referred to the court on the basis of new evidence that some original statements had been destroyed.
It was also claimed ITV documentary Red Under The Bed, broadcast during the first trials, unfairly affected them.
Lawyers for the former pickets said a “covert Foreign Office agency” known as the Information Research Department helped make the 1973 show.
Danny Friedman QC, representing 12 of the pickets, said the IRD had consulted MI5 about the programme and added: “A covert executive agency played a part in... propagandising against the core subject matter of the proceedings.
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“It is clear now that the higher echelons of the state bore responsibility for deliberate covert involvement in the production of the programme.
“In all the circumstances, the approach taken to broadcasting this programme has rendered the convictions unsafe.”
But lawyers for the Crown Prosecution Service argued the convictions were safe and that the appeals should therefore be dismissed.
Ricky Tomlinson, 81, said ahead of the hearing: “It will have taken nearly 50 years for us to have our day in court and for the truth to come out.”
The hearing is due to finish today but judgement is expected at a later date.
