Members of Parliament (MPs) on both sides of the assisted dying debate have cautioned against the “extraordinary risk” of advancing the bill through an obscure parliamentary tactic if it remains obstructed by the House of Lords.

In a critical communication ahead of the upcoming vote on Friday, two Labour MPs—Gareth Snell, who supports the bill, and Meg Hillier, who opposes it—expressed their concerns. They claimed that MPs are being faced with a “this or nothing” ultimatum and warned that invoking the Parliament Act to bypass the Lords could lead to “a constitutional showdown” with significant implications.

Snell and Hillier emphasized that the primacy of the elected House of Commons is not merely a right to impose its will but a duty to wield its authority judiciously. “Our responsibility to exercise our power with the greatest of care must not be overlooked,” they stated.

The assisted dying legislation is set to return to the Commons on Friday as a private member’s bill after its earlier iteration passed the House of Commons but was effectively blocked by a small number of peers. Although there was extensive debate among peers, the bill was derailed due to numerous amendments proposed in the House of Lords.

Initially sponsored by Kim Leadbeater, the bill has been revived by Labour MP Lauren Edwards. It was previously approved by a margin of 23 votes in the Commons last year. Advocates in both chambers assert that they could utilize the Parliament Act of 1911 to override the Lords if the Commons votes in favor of the bill again.

However, some MPs have voiced concerns about employing the act to circumvent the House of Lords on such a significant matter. The proposed legislation would permit adults suffering from terminal illnesses with less than six months to live to choose to end their lives, contingent upon approval from a panel of experts.

The Parliament Act, revised in 1949, has been invoked only a few times to enact laws without the Lords’ consent, including the decriminalization of homosexuality and the prohibition of fox hunting. For the act’s override mechanism to be triggered, a bill must be reintroduced and passed in its original form in the new parliamentary session after the previous session concludes.

In their letter, Snell and Hillier articulated that the insistence of the bill’s proponents on using the Parliament Act means there would be no opportunity for “practical or worthwhile amendments” to be proposed, despite concerns raised by hospices, medical professionals, legal organizations, and others.

They warned, “This represents an extraordinary risk for us to undertake. While we recognize that the colleagues advocating for this bill are acting in good faith and seeking to initiate a much-needed discussion on a public issue, the ramifications of this week’s actions extend far beyond the immediate matter at hand.”

Supporters of the bill contend that amendments can indeed be made by the Lords if they allow the bill to proceed to a vote in the customary manner. In a prior instance, a limited group of peers, opposing the bill, prevented the House of Lords from voting by submitting over 1,000 amendments, ultimately causing the bill to run out of time for debate as the parliamentary session concluded, resulting in its automatic dismissal.