Wednesday's vote is on a motion that the temporary powers in the Coronavirus Act "should not yet expire."
That is the wording specified in the act - framed as a straight yes or no question - which means that Mr Speaker may not think it proper to allow an amendment to be put - and even if he did, and it passed, it is not clear that any amendment would carry legal force.
Nearly everyone in Parliament accepts that at the start of the pandemic, the government had to move fast to implement the lockdown and the measures around it - and some of the legislative weapons involved were inevitably rather blunt.
But Parliament has now been back for several months, and the sight of
major restrictions on civil liberties, backed up by swinging fines, being signed into law by ministers in regulations - know as statutory instruments (SIs) - now grates on MPs across the parties.
In normal times, all kinds of regulations go through Parliament almost unnoticed, and usually with little more than perfunctory rubber-stamping.
Some can be "prayed against" - requiring them to be debated before they can take effect - others (called Made Affirmative Statutory Instruments) come into effect immediately, but do have to be debated after the event, usually within 28-40 sitting days.
According to the parliamentary think tank, the Hansard Society,
247 Coronavirus-related SIs have been laid before Parliament, 60 of them made affirmatives.
The list of SIs includes local lockdowns, mask-wearing regulations, extension of pre-trial custody, denial of prison visits, travel regulations, listing and de-listing exempt countries, and of course the fines for transgressors
So these are not trivial matters.
Now Graham Brady, the chairman of the Conservatives' backbench 1922 Committee has demonstrated that he has the numbers to defeat the government if it carries on pushing through pandemic measures which restrict civil liberties, without consulting Parliament first.