 The new corporation was required to appoint a Watch Committee and a police force under the provisions of the County and Borough Police Act 1856.In 1947, the City of Peterborough Constabulary amalgamated with the Liberty of Peterborough Constabulary, which had shared its chief constable with Northamptonshire until 1931 and Peterborough thereafter, to form the Peterborough Combined Police force.This, in turn, merged into Mid-Anglia Constabulary in 1965 and was renamed Cambridgeshire Constabulary in 1974.