The Assisted Dying Bill has been approved by the House of Commons. But unless the Parliament Act is invokved, it also needs the approval of the House of Lords if it is to become law. What constitutional role will the Lords play in this process — and would it be undemocratic for the unelected upper chamber to block the Bill?
The Terminally Ill Adults (End of Life) Bill (or the Assisted Dying Bill as it is more often referred to) has now completed its passage through the House of Commons. 314 MPs voted in favour while 291 voted against, yielding a majority of 23. Under the process whereby Bills become Acts of Parliament, the Bill will now move to the House of Lords, where it will go through a process similar to that which it underwent in the House of Commons.
Normally, a Bill can only become an Act (and hence an enforceable law) if it is approved by both the Commons and the Lords (as well as going through the purely formal process of being granted Royal Assent). If a Bill (like the Assisted Dying Bill) that starts off in the Commons is amended by the Lords, it returns to the Commons, which has to decide whether to approve or reverse the amendments. If the amendments are reversed, the Bill must go back to the Lords, which itself must decide whether to approve the Bill in its latest form. That process, informally known as ‘legislative ping-pong’, continues until both Houses agree on the same version of the Bill. Only at that point can it go for Royal Assent and become an Act. If the two Houses cannot agree, the Bill cannot go for Royal Assent and cannot become law (subject to an important exception explained below).
The House of Lords as a revising chamber
Given that the Commons is an elected chamber and that the Lords is not, the assumption might well be made that it would be improper, including on democratic grounds, for the Lords to refuse to approve the Bill now that it has secured a majority in the Commons. That, however, cannot be right. Or at least, if it is, it signifies that the House of Lords — if it must simply rubber-stamp Bills sent to it by the Commons — serves no useful purpose. In fact, the Lords is generally recognised as serving a highly valuable purpose as a ‘revising’ chamber: that is, as a chamber that takes legislation considered by the House of Commons and looks at it again, making amendments when the House of Lords concludes that they are warranted.
In this way, legislation, which may well have received inadequate scrutiny in the Commons, is often improved — a point that is underlined by the fact that many Lords amendments are subsequently agreed by the Commons. Often, therefore, the amendment of legislation by the Lords forms part of a collaborative, rather than combative, legislative process, with the two Houses fulfilling complementary roles. That said, it is also the case that the Lords generally acknowledges the greater democratic legitimacy of the Commons by ultimately giving way when matters reach the stage of legislative ping-pong. However, it is also the case that, in respect of the Assisted Dying Bill, a number of MPs referred during the Third Reading debate to the role they expected the Lords to play in improving the Bill.
Where does all of this leave us in relation to the Assisted Dying Bill? It is certainly possible, indeed likely, that the Lords will make amendments, in which case the Bill will have to return to the Commons — which, in turn, will need to decide whether to agree or reverse such amendments. Given the modest size of the majority the Bill secured in the Commons, and the position of many MPs that they support the principle of assisted dying but have misgivings about the safeguards in this particular Bill, it is entirely conceivable that some amendments made by the House of Lords might go on to be approved by the Commons. It follows that the Bill as it exists today is not the final word, and that any eventual Act of Parliament might differ, at least on points of detail.
Could the Lords block the Bill?
Is there, however, any possibility of the Lords simply refusing to approve the Bill at all — whether by voting it down or, if does not take that step, by producing a deadlock situation if, at the ping-pong stage, the Commons (say) refuses to approve additional safeguards the Lords have inserted by way of amendments? In constitutional terms, nothing would prevent the Lords from doing such things. Sometimes, an objection to legislative obstinacy in the House of Lords is the ‘Salisbury convention’, according to which the Lords should not vote down government bills that give effect to government manifesto commitments — a norm that is intended to prevent a government lacking a majority in the Lords from being thwarted in the enactment of its legislative programme. But the Salisbury convention can have no application to the Assisted Dying Bill, which is a private members’ bill rather than a government bill, and which, in any event, does not reflect any government manifesto commitment.
The other matter that needs to be considered in this context is the Parliament Act 1911 (as amended by the Parliament Act 1949), section 2 of which provides that if a Bill is passed by the House of Commons in two successive parliamentary sessions (each of which normally lasts for a year) but is rejected by the House of Lords in each of those sessions, it can be sent for Royal Assent anyway as long as a year has elapsed, ‘notwithstanding that the House of Lords has not consented to the Bill’. The Parliament Act 1911 thus accords legal recognition to the democratic primacy of the House of Commons by enabling the Lords to delay (by one year), but not ultimately to block, the enactment of legislation that the Commons has approved. This aligns with the Lords’ role as a revising chamber, enabling it, in effect, to advise the Commons to amend Bills that it has passed but not, in the end, to stop from Commons from having its own way.
The existence of the Parliament Acts regime thus has two effects that are important to the passage of the Assisted Dying Bill. First, it removes the possibility of the Lords undemocratically preventing its enactment because the Bill can be sent for Royal Assent without the Lords’ consent if the Commons follows the procedure in the 1911 Act. Second, this, in turn, undermines any argument that it would be undemocratic or otherwise constitutionally improper for the Lords to vote down the Bill. In this way, the Parliament Acts regime seeks to strike a balance between acknowledging the democratic primacy of the Commons while ensuring that the Lords’ role as a revising chamber is a meaningful one. Enforcing a 12-month delay by voting down the Assisted Dying Bill and requiring the Commons to proceed under the Parliament Acts is certainly not a step that would be taken lightly by the Lords, but it is a step that is legally open to the upper chamber and which — if, for example, it had serious concerns about the content of the Bill and the adequacy of the scrutiny it had received in the Commons — would be consistent with its important constitutional function of prompting the elected Commons to reflect and think again.
Another way of putting this point is by pointing out that the Parliament Acts regime reflects not only the view of Parliament as to the balance of power between its two chambers but also, and specifically, the view of the democratically elected House of Commons. This point follows from the fact that the Parliament Acts regime — which defines that balance of power by determining the extent of the Lords’ capacity to delay legislation and the corresponding capacity of the Commons to legislate unilaterally — can itself be, and has in fact been, amended by the Commons unilaterally using that the Parliament Acts procedure. That is precisely what happened when the Parliament Act 1949, which reduced the Lords’ delaying power from two years to one year, was enacted. The Lords did not consent to the 1949 Act, and so the Commons — after the then-requisite two-year delay — enacted it unilaterally under the 1911 Act. The validity of the 1949 Act was upheld, decades later, by the Appellate Committee of the House of Lords (which would later be replaced by the Supreme Court) in the Jackson case. The upshot is that the current power of the House of Lords to delay legislation by one year, after which it can be enacted unilaterally by the Commons, has the clear democratic imprimatur of the Commons precisely because it lies within the capacity of the latter further to adjust the balance of power, by legislating unilaterally under the Parliament Acts procedure, should it wish to do so. It is therefore not merely the case that it is legally possible for the House of Lords to delay the enactment of legislation for a year; it is also the case that, if and when the Lords chooses to do so, it acts pursuant to a process that reflects a balance of power determined and blessed by the democratic chamber. In such circumstances, it is difficult to see how it can coherently be argued that judicious use by the House of Lords of its delaying power is democratically dubious or otherwise constitutionally improper.
Private members’ bills and the Parliament Acts
Normally when the Parliament Acts are in play, the bill will be a government bill, meaning that the government, should it wish to do so, can straightforwardly reintroduce the bill in the next session. Matters would be complicated by the fact that the Assisted Dying Bill is a private members’ bill. The Hansard Society says that ‘[i]n practice’ the Parliament Act procedure ‘can only be applied to Government Bills as it would take a very peculiar combination of circumstances, challenging to orchestrate, for a Private Member’s Bill (PMB) to be passed using the Parliament Act procedures’.
However, it is not impossible for the Parliament Act procedure to be used in relation to a private members’ bill. For example, another MP who succeeded in the next session’s private members’ bill ballot could reintroduce the bill — although there is no guarantee that a sympathetic MP would come high enough up the ballot. Indeed, the difficulty of using the Parliament Act procedure in relation to a private members’ bill is even greater when one factors in the need to ensure that identical versions of the bill must be approved in two successive sessions, meaning that a backbench MP who reintroduces a private members’ bill in a successive session must guard it against amendment if the Parliament Act procedure is to be used.* It might therefore be argued that the practical difficulty of enacting private members’ bills under the Parliament Act procedure makes it undemocratic for the Lords to thwart such bills even if it is not, for the reasons given, undemocratic for the Lords to delay government bills. However, the answer to that objection is surely that there would be nothing to prevent the government from taking this matter forward itself if it wished to do so and if no suitable MP could be found to reintroduce the Bill in the next session.
Whether the House of Lords will be willing to make significant amendments to, or even to vote down, the Assisted Dying Bill remains to be seen. It is also a political matter — but one that must be approached on the basis of an accurate appreciation of the legal and constitutional position. Any argument that it would be undemocratic or otherwise constitutionally suspect for the Lords to do anything other than rubber-stamping the Bill would be wide of the mark. Because the Bill is not a government bill, the Lords’ powers are not conventionally constrained by the Salisbury doctrine. And while it is a power that is rightly used very sparingly, the Lords’ ability to delay legislation for one year is an important part of a constitutional settlement that seeks to balance the democratic primacy of the Commons and the Lords’ role as a revising chamber.
* I am indebted to Paul Evans, former Clerk of Committees in the House of Commons, for highlighting this point to me. This post was lightly amended on 11 September 2025, ahead of the Second Reading debate in the House of Lords.
Public Law for Everyone 