In the United Kingdom there are at least six Lords (or Lady) Commissioners of His Majesty's Treasury, serving as a commission for the ancient office of Treasurer of the Exchequer.

Since the formation of the office of Prime Minister (including in the case of Sir Robert Walpole as the inaugural holder), it has been typical for the incumbent to assume also the position of First Lord of the Treasury.

These junior ministerial positions are, in descending order of rank: Historically, the Chancellor of the Exchequer was also the First Lord of the Treasury, and usually by extension Prime Minister as well.

However, the increasing sophistication of government spending led to the development of the chancellorship into a more refined position of finance minister, and so gradually particularised the office in a way less suitable for headship of the ministry overall.

From the Glorious Revolution and onwards it had become increasingly constitutionally untenable for the person setting fiscal policy (i.e. the Chancellor) to reside in the House of Lords, a principle which was embedded permanently in the constitution from 1718 with the resignation of James Stanhope, 1st Earl Stanhope (note this excepts the brief tenures of certain Lord Chief Justices, who historically assumed the office of Chancellor of the Exchequer pro tempore during vacancies, and who were often peers).

That Alec Douglas-Home, the last to assume the Premiership from the Lords in 1963, felt compelled to disclaim his peerage and take up a seat in the Commons shows that the convention had, by that time, become well-entrenched.

However, when Sir Robert Peel returned to office for his non-consecutive second term he elected to be First Lord of Treasury, a title he had naturally assumed in his first ministry wherein he had also served as Chancellor.

From that point onwards, the Second Lordship, save on the rare occasion that the Prime Minister holds both 10 and 11 Downing Street, has been permanently vested in the Chancellor.

Indeed, even after decades of the emergence of the premiership, William Pitt the Younger proffered that the Prime Minister "ought to be the person at the head of the finances.

Salisbury, as a marquess of vast independent wealth,[8] had no use of an official residence, instead living in his grander town house at 20 Arlington Street in St James's, and could instead bestow it as a perquisite to other ministers, along with the First Lordship itself.

Since the Prime Minister was a Lord Commissioner of the Treasury, prior to the reform he had had ex officio oversight of these portfolios, but it was felt more proper for the civil service to be held outside of a particularised department.

Boris Johnson held the position of Minister for the Union, which he created to display his commitment to strengthening the bond of the four nations of the United Kingdom.