Trade union activists targeted blacklisting employers on a 20 November day of action.
The day, which was called by the TUC, saw demonstrations, rallies, and other direct actions targeting companies such as Sir Robert McAlpine, a construction firm.
An ongoing parliamentary enquiry has revealed that the firm spent £28,000 on union-busting and blacklisting activities.
Demonstrations were held in Birmingham, Cardiff, Glasgow, Hemel Hempstead, London, Leeds, Manchester, Newcastle, Wolverhampton, and elsewhere.
Campaigners from the Blacklist Support Group say the government should properly