Main Functions of Parliament
Parliament sits at the heart of the United Kingdom's constitutional framework. Its primary function is the formal enactment of the government's legislative proposals. This is an important distinction: Parliament does not, in the main, itself conceive of or draft legislation; rather, it provides the constitutional mechanism through which the executive's proposals are scrutinised, debated, and ultimately given legal force.
Beyond formal enactment, Parliament performs four further essential functions. First, it provides the personnel of government — ministers are drawn from, and remain accountable to, Parliament. Second, it legitimises governmental action by publicly debating and approving measures taken in the name of the Crown. Third, it scrutinises legislative bills, subjecting proposals to detailed examination before they pass into law. Fourth, it authorises public expenditure, granting the funds necessary for the discharge of statutory duties and the implementation of legislative programmes.
The House of Commons
Composition and Election
The House of Commons is the elected chamber of Parliament. It currently comprises 650 members of Parliament (MPs), each representing a single geographical constituency and returned by the first-past-the-post system. A proposal was made to reduce the number of seats to 600 following a Boundary Commissions review, but this reduction was ultimately not implemented and the House retains 650 seats.
The Speaker
The House of Commons is presided over by the Speaker, who is elected by fellow MPs. The Speaker's role is to maintain order during debates, call members to speak, and ensure that proceedings are conducted in accordance with parliamentary convention and procedure. By long-standing convention, the Speaker acts impartially and resigns from any party affiliation upon election to the office.
Limits on Ministerial Office
The number of holders of ministerial office who may sit in the House of Commons is limited by statute. Under s 2 House of Commons Disqualification Act 1975, no more than 95 holders of ministerial office may sit and vote in the Commons at any one time. This restriction serves to prevent the executive from dominating the legislature through sheer weight of ministerial numbers.
The House of Lords
Overview of Composition
The House of Lords is the unelected, second chamber of Parliament. Most of its members are peers appointed by the monarch on the advice of the Prime Minister. The chamber is composed of two broad categories: Lords Temporal and Lords Spiritual.
Lords Temporal: Life Peers
Life peers are appointed under the Life Peerages Act 1958, which enables the Crown to confer a life peerage — and with it the right to sit and vote in the House of Lords — upon any person, regardless of whether they hold an hereditary peerage. Life peerages are not heritable; they extinguish on the death of the holder. The Life Peerages Act 1958 has been the principal vehicle for Lords appointments since its enactment, and life peers now constitute the substantial majority of the chamber's membership, numbering approximately 770 as of 2025, though this figure fluctuates as appointments are made and members leave.
Lords Temporal: Hereditary Peers
Prior to 1999, all holders of hereditary peerages were entitled to sit and vote in the House of Lords. The House of Lords Act 1999 fundamentally altered this position. Under that Act, present or future holders of a hereditary peerage no longer have the right to sit and vote in the House of Lords by virtue of their peerage alone. An exception was, however, preserved: up to 92 hereditary peers retained the right to sit, elected by their fellow hereditary peers. This compromise was intended as a transitional arrangement pending further reform, though it has endured for over two decades.
Lords Spiritual
The Lords Spiritual comprises 26 senior clergy of the Church of England. The Archbishops of Canterbury and York sit by right. The remaining 24 places are occupied by diocesan bishops, with the Bishop of London, the Bishop of Durham, and the Bishop of Winchester sitting by right of office, and the remaining 21 places rotating amongst the other diocesan bishops in order of seniority of appointment.
Reform Debates: The 2011 White Paper
The composition of the House of Lords has been the subject of sustained reform debate. In May 2011, the coalition government published a White Paper proposing a substantial reduction in the size of the chamber to 300 members, with 80% of members to be elected and 20% appointed. Despite considerable discussion, this proposal was not enacted and the House of Lords remains an entirely appointed — save for the 92 hereditary peers — and unelected chamber.
Summoning and Term of Parliament
The Requirement to Summon Parliament
Parliament must be summoned at least every three years. This requirement derives from the Meeting of Parliament Act 1694. By longstanding constitutional convention, however, Parliament in practice meets throughout the year, and the statutory minimum is of historical rather than operational significance.
Maximum Parliamentary Term
The maximum life of a single Parliament is five years, as provided by the Parliament Act 1911. Historically, most Parliaments have not served the full five-year term, having been dissolved earlier at the Prime Minister's request.
Fixed Terms and the Return to Flexible Dissolution
An important modification to the traditional position was introduced by the Fixed-term Parliaments Act 2011, which sought to fix the duration of parliamentary terms at five years and removed the Prime Minister's unfettered power to request early dissolution. Under the Fixed-term Parliaments Act 2011, early elections could only be triggered in specified circumstances. However, following the political experience of 2017 and 2019 — both of which required legislative workarounds — the Fixed-term Parliaments Act 2011 was subsequently repealed by the Dissolution and Calling of Parliament Act 2022. The Dissolution and Calling of Parliament Act 2022 restored the prerogative power of the monarch to dissolve Parliament at the Prime Minister's request, returning the constitutional position broadly to that which obtained before 2011.
Parliamentary Sessions
Opening and Prorogation
A parliamentary term is divided into sessions, each of which typically runs from October or November of one year to approximately the same point in the following year. A session is formally brought to a close by prorogation, which is effected by Royal Decree. Prorogation suspends parliamentary business but does not dissolve Parliament.
Carry-Over of Bills
A practical consequence of the sessional structure is that bills which have not completed their parliamentary passage by the time of prorogation ordinarily lapse, meaning the entire legislative process must recommence in the following session. By agreement between the parties, however, bills may be carried over from one session to the next, preserving the legislative progress already made and avoiding needless duplication of parliamentary time.
Types of Bills
Public Bills
Public bills are measures of general application affecting the public at large. They fall into two subcategories.
Government bills are introduced by ministers on behalf of the executive and form the principal vehicle through which government policy is translated into law. They typically originate from manifesto commitments, White Papers, Law Commission reports, or responses to external events.
Private members' bills are introduced by individual MPs or peers who are not acting in a ministerial capacity. Such bills may address matters of principle or conscience, highlight particular social issues, or seek relatively modest legal changes. Although private members' bills are considerably less likely than government bills to pass into law — owing to the limited time allocated to them — a number of significant pieces of legislation have originated as private members' bills.
Private Bills
Private bills, which should be distinguished carefully from private members' bills, are measures promoted by particular bodies — typically local authorities, public utilities, or commercial undertakings — to obtain powers for themselves beyond, or in modification of, the general law. They do not affect the public generally and follow a distinct procedural track from public bills, including an opportunity for affected parties to petition against them.
The Legislative Process for Public Bills
First Reading
The first reading is a purely formal stage. The title of the bill is read out and a date is set for the second reading. No debate occurs and no vote is taken. The bill is then formally printed and made available to members.
Second Reading
The second reading is the principal debate on the general principles and purposes of the bill. Members consider whether the bill is desirable in principle, and the vote at the conclusion of the second reading debate is effectively a vote on whether to proceed with the measure at all. It is at this stage that the most significant political opposition to a government bill will typically crystallise.
Committee Stage
Following a successful second reading, the bill proceeds to the committee stage, at which its provisions are examined clause by clause in detail. In the House of Commons, a bill is usually referred to a general (standing) committee of between 16 and 50 members, appointed by the Committee of Selection with party representation proportionate to the composition of the House. Bills of constitutional significance, bills concerned with government expenditure, and some relatively uncontroversial bills may instead be referred to the Committee of the Whole House, in which all MPs may participate.
At committee stage, amendments to individual clauses may be proposed, debated, and voted upon. This is the stage at which the detailed content of legislation is most thoroughly interrogated.
Report Stage
After the committee stage, the bill — incorporating any amendments made in committee — is reported back to the full House. At the report stage, further amendments may be proposed, debated, and voted upon. This provides the House as a whole with an opportunity to revisit and refine the work of the committee, including the opportunity to reverse amendments made in committee or to add new provisions.
Third Reading
At the third reading, the bill is considered in its final, amended form. Debate at this stage is normally brief. Only verbal amendments — minor corrections of a drafting or typographical nature — may be made. The third reading represents the final opportunity for the originating House to vote on the bill as a whole.
Proceedings in the House of Lords
Proceedings in the House of Lords do not begin until after the bill has completed its third reading in the House of Commons. The Lords then subject the bill to a broadly parallel process of readings and examination. A notable procedural difference is that the committee stage in the House of Lords is almost always conducted as a Committee of the Whole House, permitting all peers to participate in detailed scrutiny, in contrast to the Commons practice of using smaller standing committees.
If the House of Lords amends the bill, it must be returned to the House of Commons for consideration of those amendments. If the Commons restores the original wording by rejecting the Lords' amendments, the Lords will ordinarily accept the Commons' position, and the bill will proceed in the form preferred by the elected chamber. Where persistent disagreement between the chambers arises — a situation known as "ping-pong" — the provisions of the Parliament Act 1911 (as amended by the Parliament Act 1949) may ultimately be invoked to allow certain bills to receive Royal Assent without the Lords' consent.
Royal Assent
Once a bill has been passed by both Houses in the same terms, it is presented for Royal Assent. Royal Assent is the formal mechanism by which the monarch — now acting entirely on constitutional convention without any personal discretion — gives approval to the bill, converting it into an Act of Parliament. Only after Royal Assent does a bill acquire the force of law.
It should be noted that the commencement of an Act is not automatically simultaneous with Royal Assent. An Act may provide for its own provisions to come into force on a future date, which may itself be determined by a commencement order made by way of delegated legislation under the Act. This allows the government to bring different provisions of a lengthy or complex Act into force at different times as the necessary administrative preparations are made.