Cornwall County Constabulary establishment of 500 and an actual strength of 446. On 1 April 1967 it amalgamated with Devon and Exeter Police and Plymouth City Police to form Devon and Cornwall Constabulary. Cornwall County Constabulary Cornwall County Constabulary was the Home Office police force for the county of Cornwall, England, until 1967. The force was formed in 1857. It absorbed Bodmin Borough Police in 1866, Liskeard Borough Police in 1877, Launceston Borough Police in 1883, Falmouth Borough Police, Helston Borough Police, Penryn Borough Police and St Ives Borough Police in 1889, Truro City Police in 1921, and Penzance Borough Police and the
Constitutional status of Cornwall Cornwall has a "de jure" status apart as a sovereign Duchy extraterritorial to England. A commonly cited basis for this argument is a case of arbitration between the Crown and the Duchy of Cornwall (1856–1857) in which the Officers of the Duchy successfully argued that the Duchy enjoyed many of the rights and prerogatives of a County palatine and that although the duke was not granted Royal Jurisdiction, was considered to be quasi-sovereign within his Duchy of Cornwall. The arbitration, as instructed by the Crown, was based on legal argument and documentation, led to the Cornwall Submarine Mines Act of