Abstract: This article critically considers a state-centred approach to public law that has been epitomised in Martin Loughlin’s claim that the concept of the state is the sine qua non of public law. More precisely, the article argues against two theoretical tenets that underlie this state-centred approach. The first tenet is the consideration of state authority as absolute authority. The second tenet claims that public law has a deep distinctness from all other fields of law, which are contrasted to it by being described as constituting the realm of ordinary law. The article also challenges the ability of the aforementioned state-centred approach to fully account for the status and role of the doctrine of parliamentary sovereignty in the UK constitutional order. This challenge is discussed in light of a distinction between state sovereignty and parliamentary sovereignty.