The Royle Family actor Ricky Tomlinson is among the campaigners urging the government to release documents relating to the "Shrewsbury 24" case.
Today he accused ministers of telling "bare-faced lies" in refusing to release all the documents because of "national security", which he believes proves the arrests were politically motivated.
Tomlinson was one of six building workers imprisoned in 1973 after being arrested for picketing following a national strike.
Steve Murphy, general secretary of the building workers' union Ucatt, is supporting the campaigners' cause.
He said: "The news that the government papers will not be published for at least another 10 years is appalling.
"What they are hiding is a massive government conspiracy and shows that the home secretary of the day connived with the police and security forces at the behest of construction companies to make an example of ordinary workers."
Using Jim Royle's catchphrase, he added: "National security, my arse."
More top news
David Cameron is facing growing pressure for the UK to take in more of the many thousands of migrants fleeing to Europe.
China has put on its biggest display of military might in a parade to commemorate victory over Japan in World War Two.
Hungarian Prime Minister Viktor Orban is to meet with European Union leaders in Brussels today to discuss the migration crisis.