Revolutionary settlement

Because the Premiership was not intentionally created, there is no exact date when its evolution began. A meaningful starting point, however, is 1688 when James II fled England and the Parliament of England confirmed William and Mary as joint constitutional monarchs, enacting legislation that limited their authority and that of their successors: the Bill of Rights (1689), the Mutiny Bill (1689), the Triennial Bill (1694), the Treason Act (1696) and the Act of Settlement (1701).^[10] Known collectively as the Revolutionary Settlement, these acts transformed the constitution, shifting the balance of power from the Sovereign to Parliament. They also provided the basis for the evolution of the office of Prime Minister, which did not exist at that time.

Treasury Bench

The Revolutionary Settlement gave the Commons control over finances and legislation and changed the relationship between the Executive and the Legislature. For want of money, Sovereigns had to summon Parliament annually and could no longer dissolve or prorogue it without its advice and consent. Parliament became a permanent feature of political life.^[11] The veto fell into disuse because Sovereigns feared that if they denied legislation, Parliament would deny them money. No Sovereign has denied royal assent since Queen Anne vetoed the Scottish Militia Bill in 1708.^[12]

Late in the 17th century Treasury Ministers began to attend the Commons regularly. They were given a reserved place, called the Treasury Bench, to the Speaker's right where the Prime Minister and senior Cabinet members sit today

Treasury officials and other department heads were drawn into Parliament serving as liaisons between it and the Sovereign. Ministers had to present the government's policies, and negotiate with Members to gain the support of the majority; they had to explain the government's financial needs, suggest ways of meeting them and give an account of how money had been spent. The Sovereign’s representatives attended Commons sessions so regularly that they were given reserved seats at the front, known as the Treasury Bench. This is the beginning of "unity of powers": the Sovereign's Ministers (the Executive) became leading members of Parliament (the Legislature). Today, the Prime Minister (First Lord of the Treasury), the Chancellor of the Exchequer (responsible for the budget) and other senior members of the Cabinet sit on the Treasury bench and present policies in much the same way Ministers did late in the 17th century..

Standing Order 66

After the Revolution, there was a constant threat that non-government members of Parliament would ruin the country's finances by proposing ill-considered money bills. Vying for control to avoid chaos, the Crown's Ministers gained an advantage in 1706 when the Commons informally declared, "That this House will receive no petition for any sum of money relating to public Service, but what is recommended from the Crown." On 11 June 1713, this non-binding rule became Standing Order 66: that "the Commons would not vote money for any purpose, except on a motion of a Minister of the Crown." Standing Order 66 remains in effect today (though renumbered as no. 48),^[13] essentially unchanged for three hundred years.^[14]

Empowering Ministers with sole financial initiative had an immediate and lasting impact. Apart from achieving its intended purpose – to stabilise the budgetary process – it gave the Crown a leadership role in the Commons; and, the Lord Treasurer assumed a leading position among Ministers.

The power of financial initiative was not, however, absolute. Only Ministers might initiate money bills, but Parliament now reviewed and consented to them. Standing Order 66 therefore represents the beginnings of Ministerial responsibility and accountability.^[15]

The term "Prime Minister" appears at this time as an unofficial title for the leader of the government, usually the head of the Treasury.^[16] Jonathan Swift, for example, wrote in 1713 about "those who are now commonly called Prime Minister among us", referring to Sidney Godolphin, 1st Earl of Godolphin and Robert Harley, Queen Anne's Lord Treasurers and chief ministers.^[17] Since 1721, every head of the Sovereign's government – with one exception in the 18th century (William Pitt, the Elder) and one in the 19th (Lord Salisbury) – has been First Lord of the Treasury.