Will this week end any prospect of a shake-up to parliamentary boundaries before the next election? On Tuesday MPs will vote on Lords amendments to the Electoral Registration and Administration Bill - which include an amendment postponing any boundary review beyond the end of the current parliament.
The Commons vote on this issue could release a lot of nasty toxins into the Coalition's bloodstream.
The backstory to all this is a little tangled. The original Coalition Agreement linked a referendum on electoral reform (which the Lib Dems wanted) to a reduction in the number of MPs and, crucially, to an equalisation of constituency sizes.
It's a long-standing Conservative complaint that urban, mainly Labour seats have smaller electorates than Conservative seats, and that this loads the electoral dice against them. Having got (and lost) their referendum, Conservatives expected the Lib Dems to stick to their side of the deal and vote through the boundary changes - but Lib Dem MPs, infuriated by the way the Conservatives fought that referendum, with a personalised campaign against Nick Clegg, and by the subsequent defeat of Lords reform, are now attempting to block the new boundaries, with the enthusiastic backing of Labour.
(Incidentally, Labour argues that many people living in inner city areas are not on the electoral role, so the figures underestimate the populations of their constituencies.)
In the Lords, this issue, for the first time, pitted Conservatives and Lib Dem ministers against each other in the voting lobbies. The same looks set to happen in the Commons, but the maths could be interesting.
It is arithmetically possible for the Conservatives to beat a combined Labour-Lib Dem vote, if enough of the smaller parties back them. But the word from the Scottish and Welsh nationalists is that they won't - and they're pretty categorical about it. Throw in opposition from DUP MPs and maybe even some Conservatives, and the measure looks doomed.
Of course you never know. Maybe the subtle mind of the government Chief Whip, Sir George Young, will find a way to induce the minor parties to side with the Conservatives, but it seems to me that the main impact of the vote will be to poison Coalition relations. And some Tory retaliation may follow.....
Here's my look at the rest of the parliamentary agenda....
On Monday, the Commons meets at 2.30pm for work and pensions questions, and then (unless there's a ministerial statement or urgent question), MPs will finish their consideration of the Succession to the Crown Bill.
The Labour MP Chris Bryant has an amendment down to remove the section that allows the monarch to approve the marriage of the first six people in the line of succession - and various amendments on questions like appointing a regent as head of the Church of England, if the monarch is not a member, are still on the order paper. It's up to the chair how many of these will be called. In any event, the bill will almost certainly be sent off to the Lords by the end of the day - and proceedings conclude with an adjournment debate on funding for basketball, led by the Conservative Stephen Mosely.
In the Lords (from 2.30pm) questions from peers range across the record-low sea ice extent in the Arctic Ocean during the past year and the likely future of oil prices , before peers continue the marathon committee stage consideration of the Growth and Infrastructure Bill. This is day two of five. There will also be a short debate on the future of Air Passenger Duty.
Meanwhile watch out for one dry-looking amendment to be discussed in Grand Committee on the Enterprise and Regulatory Reform (ERR) Bill. The government will propose deleting section 52 of the Copyright, Designs and Patents Act 1988 - which could have some major implications.
What this deletion would do is to change the copyright protection system for industrial designs which are mass produced, from 25 years after registration to 70 years after the death of the designer. So it will bring back into copyright products that are currently out of copyright - affecting many thousands of consumers of such products and designs, as well as greatly increasing the potential earnings of rights' holders.
The Commons meets at 11.30am for Treasury questions on Tuesday, and then the Conservative MP Edward Leigh has a Ten Minute Rule Bill. His Equality (Marriage) (Amendment) Bill is designed to provide legal protection for those who back the current definition of marriage - he points to the case of a man demoted at work for comments on Facebook that gay marriage was "an equality too far" - and he wants to make sure people like teachers, foster carers and others are not disciplined for their beliefs.
Then it's on to that set-piece Coalition spat, the consideration of Lords amendments to the Electoral Registration and Administration Bill, including the one postponing the implementation of the review of Commons constituency boundaries. Following that, maybe MPs will find the report stage and third reading of the HGV Road User Levy Bill quite soothing.
Over in Westminster Hall (from 9.30am) there are a series of debates led by backbenchers - and the first one on the batting order, led by the Conservative Simon Hart, has caught my eye. In the wake of the recent prosecutions for hunting offences in David Cameron's Oxfordshire constituency, he's focusing on the role of the RSPCA as a prosecutor.
The RSPCA is Britain's most prolific private prosecutor, bringing thousands of charges a year on animal-related issues, but Mr Hart argues that its political campaigning, on hunting, for example, has become entangled with its legal activities, and that the two should be separated. Expect opponents of hunting to weigh in on the other side of the argument - this could be pretty sparky.
In the Lords (from 2.30pm) the main debate of the day is on the UK economy and the government's role in promoting growth - and it will provide the first big outing for the new Infrastructure Minister Lord Deighton. He was billed as a key figure in efforts to promote more investment in Britain, so peers will be listening closely to what he has to say. The short dinner time debate is on the future role of cultural projects and the arts in regional and economic regeneration.
On Wednesday in the Commons (from 11.30am) international development questions are followed by (sigh) prime minister's question time. Then there's a Ten Minute Rule Bill on housing market reform.
The Labour MP Gareth Thomas will call for the restriction on the right to buy in Britain's National Parks to be extended to major urban areas including London. The restriction on those who could buy certain ex-local authority properties typically takes between 10% and 20% off the full market value of an ex-council home and allows those who have lived or worked in an area for three years or more, more chance to get on the housing ladder. The idea is to help those on lower incomes in the community to have a little more access to the housing market.
The day's main business is a general debate on Europe - which will provide a taste of what life in parliament is going to be like until an EU referendum is finally held. I suspect the referendum battle is going to pervade parliamentary business for years to come - with the opposing camps using every conceivable debate, question time and select committee to make their points.... ho hum.
In the Lords (from 3pm) there's more detailed consideration of the Growth and Infrastructure Bill and a short debate on combating neglected tropical diseases.
So to Thursday, when the Commons meets at 9.30am for energy and climate change questions - an ever entertaining source of intra-Coalition sniping, and then, after the weekly statement on future Commons business, MPs move on to consider Lords amendments to the Canterbury City Council Bill, Leeds City Council Bill, Nottingham City Council Bill and the Reading City Council Bill. These are private bills which give the respective local authorities extra powers to control street trading, and this kind of bill has been subject to guerrilla ambushes from Conservative backbenchers who dislike the powers they confer. Will Christopher Chope and his allies sweep down from the hills to cause more havoc?
Then there's a rather in-house debate on proposals to give the Commons select committees a few more teeth. The suggestions were made by the Liaison Committee - the super committee of all select committee chairs, best known for its Q&A sessions with the prime minister. The government has recently responded to its report on select committee effectiveness, resources and powers - and the Liaison Committee has been disappointed with what it had to say.
Its response to the response is: "The government has not yet recognised the changed mood in the House and the strength of our resolve to achieve change" is pretty tough for them - equivalent to a red-faced, foot-stamping tantrum from a less inhibited body. There will be a motion asking MPs to keep up the pressure on ministers by endorsing their call for more powers...among other things this might be the Leader of the House, Andrew Lansley's first real test of reforming zeal. Or otherwise.
In Westminster Hall there are two general debates - one on the 30th anniversary of the Welsh-language TV broadcaster S4C, and one on the military justice system.
In the Lords (from 11am) questions range across wildlife crime and railway fares. And then peers hold a debate on the prime minister's speech on Europe. In general their lordships are rather less eurosceptic than MPs, but this will be the first parliamentary opportunity for Ukip to weigh in - and watch out for their new star turn, Lord Stevens of Ludgate.
There are a couple of backbench debates - one on the impact of student visa policy on admissions to and a short debate on industry and recent economic developments in the north-east of England.
Friday is a private members' bill day in the Commons, but on this occasion it's also Thomas Docherty day - the Labour MP has donned the mantle of departed procedure expert Andrew Dismore and managed to manoeuvre bills on some of his favoured causes into the chamber for debate. So he will propose at least a couple of the Commercial Lobbyists (Registration and Code Of Conduct) Bill, the Armed Forces (Prevention of Discrimination) Bill, the Executive Pay and Remuneration Bill, the Train Companies (Minimum Fares) Bill and the Homeowners' Mortgage Interest Rates Bill.
Pity poor Ian Lucas, whose Plastic Glasses and Bottles (Mandatory Use) Bill will not get to the wicket, unless Mr Docherty's prepared to drop a couple of those.
Of course it's not just legislative high jinks: the idea is to get a ministerial response to a couple of the ideas being floated. It can then be taken down and used in evidence.
In the Lords (from 10am) peers will be debating private members' bills from the Commons: the Antarctic Bill, the Presumption of Death Bill and the Mobile Homes Bill - and since, last week, they defeated the government and rejected an amendment promised to MPs to get a bill through the Commons, this might not be an exercise in mere rubber-stamping.