Given Corbyn's politics, firmly on the left of the wider Labour Party, it could reasonably have been assumed initially that any proposals that he might have put forward for constitutional reforms would have been quite radical in nature. Indeed, his close personal and political relationships with other party grandees, such as Tony Benn, offer a political window on what Corbyn's thinking on constitutional reform would have been had he been elected. However, a prime minister as far to the left as Corbyn remains untested in British political history, and any such reforms would also have to be measured against the successes and failures of previous Labour governments. What would a Corbyn government have meant for the British constitution?

To explore this, given the political similarities between Corbynism and Bennism (Bolton & Pitts 2018), this chapter explores Benn's framework for the establishment of a constitutional premiership, intended to strengthen the role of the legislative branch of the British constitution at the expense of the executive. Benn's constitutional premiership is rooted in the socialist principles that guide the Labour Party, advocating for a greater role for the party and its affiliates. Previous Labour governments have made some progress (or regression) in advancing constitutional premiership, although some actively resisted some elements of it. As such, this chapter determines if a Corbyn government would have represented an adherence to constitutional premiership, or continuity with the efforts of previous prime ministers to resist it.

The constitution has long been viewed as a tool through which to advance socialism. At the beginning of the twentieth century, the Labour Party emerged as a political force with a dual mandate: the socialist organizations that co-founded it sought greater common ownership of the means of production, and the trade union groups sought representation for their members within the institutions of state so that their lot might be improved (Harvey & Bather 1963: 92). This correlates with the wider aims of Bennism to promote greater political participation to advance socialism. The aims of the party were clear: to “promote socialism (whatever that may mean) by democratic means […] within the constraints of the present framework of parliamentary democracy”.