Legal background
Prior to the 2011 Act, either Parliaments were dissolved when they reached the end of their five-year terms under the Septennial Act 1715 (as amended by the Parliament Act 1911) or, more usually, they were dissolved by the Sovereign under the Royal prerogative. The exercise of the prerogative was, in practice, subject to constitutional conventions. For example, the Sovereign dissolved Parliament only when requested to do so by the Prime Minister, and in certain exceptional circumstances, the Sovereign could refuse to grant a dissolution.
	A new Parliament was summoned by Proclamation issued by the Sovereign on the advice of the Privy Council. That Proclamation triggered the issuing of the writs for parliamentary elections and writs of summons to attend the House of Lords, and appointed a day and place for the meeting of the new Parliament. In practice, if the Parliament had not reached its full term, the Proclamation summoning the new Parliament also dissolved the previous Parliament. At the same time as the Proclamation, an Order in Council was made requiring the issue of these writs.
	The long-standing position prior to the 2011 Act was that the exercise of the prerogative powers to dissolve one Parliament and call another was not reviewable by the courts. In Council of Civil Service Unions v Minister of State for Civil Service [1985] AC 374 ("the CCSU case"), Lord Roskill included the dissolution of Parliament in a list of examples of prerogative powers that in his view were not susceptible to judicial review because their nature and subject matter meant they were not amenable to the judicial process. He considered that the courts were not the place to determine whether Parliament should be dissolved on one date rather than another. 1 Following the CCSU case, in R v Secretary of State for Foreign and Commonwealth Affairs, ex parte Everett [1989] 1 QB 811, Lord Justice Taylor noted dissolving Parliament (among other examples) was not justiciable as it was "a matter of high policy" "at the top of the scale of executive functions" and therefore was not justiciable. 2
	Some prerogative powers have been held by the courts to be reviewable, both in the CCSU case and in subsequent cases. 3 It is generally accepted and understood that, before the commencement of the 2011 Act, the dissolution of one Parliament and calling of another were not susceptible to judicial review: see for example the Independent Review of Administrative Law, March 2021.
	The 2011 Act provided for fixed days for polls for parliamentary general elections. It provided that the polling day for parliamentary general elections would ordinarily be the first Thursday in May every five years. The 2011 Act also made provision to enable the holding of early parliamentary general elections. Under the 2011 Act the Sovereign did not retain any residual power to dissolve Parliament.
	In 2017 an early parliamentary general election was called under section 2(1) of the 2011 Act. For the early parliamentary election in 2019, bespoke primary legislation - the Early Parliamentary General Election Act 2019 - was needed because the two thirds majority required by the 2011 Act could not be secured in the House of Commons.
	The law governing the proceedings at a parliamentary election is set out principally in the Representation of the People Act 1983. Section 23(1) of that Act provides that such proceedings are to be conducted in accordance with Schedule 1 to the Act which sets out the Parliamentary Elections Rules. Rules 1 and 2 concern the timetable that applies leading up to polling day.