This paper aims to explain the origins of the rules of parliamentary agenda control, which can be regarded as the single most important institutional determinant of parliamentary power. Based on the premises of distributive bargaining, the paper develops a causal mechanism for the delegation of agenda control to the government majority. Given that only anti-system or anti-establishment parties strictly prefer to participate in plenary proceedings, these ‘anti’-parties potentially obstruct legislation. Such legislative obstruction by ‘anti’-parties causes establishment parties to commit themselves to procedural reform and thus triggers attempts to centralise agenda control. The delegation of parliamentary agenda powers is successful if opposition to procedural reform is confined to anti-system parties. The causal leverage of this mechanism is assessed in a process-tracing of three reform attempts in two most different cases: the initially ineffective, but then successful introduction of a closure procedure in the United Kingdom and the failed attempt to facilitate the closure in Germany.