TV star Ricky Tomlinson today made an emotional appeal for 40-year-old convictions against 24 pickets from Shrewsbury to be overturned as he revealed details of the "injustice."
The Royle Family actor was close to tears as he recalled serving 16 months in jail for charges he insisted were politically motivated.
His son and grand-daughters had faced taunts because of his conviction, he said, which was one of the reasons he continued to press for the convictions to be quashed.
The so-called Shrewsbury 24 were arrested and charged under the 1875 Conspiracy Act, with six sent to prison.
Mr Tomlinson said the picketing in 1972 had been entirely peaceful, but the group of men were arrested five months later.
Jurors at their trial were wrongly told by a court usher that the men would only be fined £50, but prison sentences were handed down, he claimed.
– Terry Renshaw, one of the pickets
There was obviously political interference from the Conservative Party in bringing the prosecutions, but Cabinet papers from the day which would prove our case will not be released because of so-called security reasons.
The Government deny it was a political trial but they cite security in refusing to release all the papers - it just doesn't add up.
Mr Renshaw, at 64 the youngest of the 24, four of whom have died, said he had been denied work because of his conviction and was not able to travel to countries such as the United States.
– Labour MP Tom Watson, who has joined the campaign
These were ordinary trade unionists fighting for their rights in an industry which was out of control. Three building workers were losing their lives every week because of the state of health and safety on sites.
"Big business was thick as thieves with the Tory party and a great injustice was done.