Fifty thousand people must put pen to paper if the Shrewsbury show trials’ survivors are ever to see justice, campaigners have said.

Political prisoner turned sitcom star Ricky Tomlinson pointed to the exposé of the “disgraceful” Hillsborough cover-up as a sign that campaigns can work.

The former plasterer was one of 24 construction workers arrested and charged after they picketed Tory peer and construction magnate Sir Robert McAlpine’s building sites in 1972 — despite advice from the then-director of public prosecutions that there was not enough evidence to secure a conviction.