Campaigners hoping to overturn convictions for conspiring to picket building sites during a national strike in 1972 have rallied support at Westminster.
Actor Ricky Tomlinson was one of those jailed at Shrewsbury Crown Court for his part in the action.
The campaingers are angry that the Government is refusing to release documents linked to the affair until 2021 on the grounds of national security.
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A large tent has been put up around the area while investigations continue.