Market Investigations Ltd v Minister for Social Security [1969] 2 QB 173 is a UK labour law case which was heard as a challenge to a decision by Government that employed National Insurance contributions were due on the payments to the worker. It took the view that establishing the common-law employment status of an employment contract requires attention to a multiple list of factors. In some regards this judgement appears to undermine the three-step reasoning in Ready Mixed Concrete (South East) Ltd v Minister of Pensions and National Insurance (RMC), which was decided the previous year. However, 'Market Investigations' involved implying the companies best-practice handbook into each of the separate contracts between the parties, whereas 'RMC' was judged purely by rational construction of