The PCS union claims some court proceeding are being delayed today by strike action.
Nottingham Magistrates Court - Down to 2 courts from 11. Delaying sentencing in high profile case v. 19 climate change protesters. #pcsm20
Pickets are also on duty outside Government offices and other departments, including the Office for National Statistics in London where the latest unemployment figures have been published.
PCS members handed out leaflets which say the dispute is the most serious ever faced by the union.
More top news
A mother has been arrested on suspicion of attempted murder after her three young children were found with their throats cut.
Ex-Cuban leader Fidel Castro has broken his silence over Cuba and the United States' attempts to repair diplomatic relations.
David Cameron has pledged to reduce the annual benefits cap to £23,000 "within the first few days" of a Conservative election win.