Amending the Immigration Bill
As I write the Conservative backbencher Dominic Raab is trying to write a new clause into the government's Immigration Bill, to prevent the right to family life being used to prevent the deportation of foreign criminals.
This is rather a novel experience for Mr Raab who, being an assiduous MP, has put down new clauses to several other bills in his short Commons career - but has never had one debated before.
What's going on in the Commons today illustrates one of the biggest weaknesses in the way MPs process bills.
They are debating a whole series of changes to the bill at report stage, which is the one opportunity for the whole House to debate the fine detail of a proposed new law and suggest changes.
And much depends on the way such debates are scheduled.
Where there's a very limited time for debate, some amendments and new clauses may not be discussed at all - just waved through in a series of votes at the end of proceedings.
And its not unheard of for new clauses to be created simply to crowd out debate of issues further down the batting order.
In other words the process is open to manipulation and can leave large and often very important chunks of legislation un-debated.
As today's report stage debate on the Immigration Bill approached, the expectation was that Mr Raab would not get to the wicket, and his proposal would fall without ever being debated.
As it turned out, the Speaker, who decides the grouping of amendments and new clauses found a way to ensure it was debated.
His placing of Mr Raab's new clause in a group concerned with the immigration system was a nifty bit of footwork that enabled MPs to debate a proposal that clearly commanded wide support.
"Helpful as always, to the government," snorted one Bercow-sceptic MP.
And, indeed, it would have been quite possible and fairly unremarkable, for Mr Speaker to have set an order of debate that would indeed have consigned Mr Raab to the outer darkness.
But surely the Speaker's job is to ensure MPs debate issues of concern?
We can add this to the calling of an extra amendment to the Queen's Speech, last year, a move which allowed euro-sceptic Tories to manifest their regret at the lack of an EU membership referendum, to the list of rulings from the Chair which have given a voice to backbenchers and discomforted ministers.
In this particular case, the Immigration Bill has been held in limbo for some months while the government tried to defuse another amendment from the Conservative Nigel Mills, extending the controls on immigration from Bulgaria and Rumania.
At one point that amendment commanded impressive backbench support but the steam has rather gone out of the campaign behind it and Mr Raab's offering has now overtaken it - to the point where there's now talk that ministers will abstain when it comes to a vote, rather than oppose it directly, and find a way to act on his concerns.