More than 20 years after the first major wave of privatisations, the trend towards using private companies to deliver public goods and services has not abated. With little left to be sold, the current government continues to find new means – more creative, but no less effective – of redrawing the boundary between private enterprise and the state.

Companies that are engaged in the delivery of traditionally public sector activities occupy an ambiguous position. To what extent, if at all, are they bound by public law principles? Some might imagine that they are immune. When Birmingham City Council recently threatened to seek a judicial review of Royal Mail’s post office closure programme for the city, Royal Mail (in fact one of the few companies still wholly owned by the Government) publicly responded that it could not be judicially reviewed because it had been allowed ‘commercial freedom’.