During the AV Campaigns evidence for the Scottish Affairs Committee, David Mowat (Conservative MP) brought up in passing the idea that devo-max could involve an element of reduction of Scottish seats in Westminster in exchange for powers, an idea that's appearing in a few places (just a few examples, this speech by John Major and this article in the Scotsman) and I thought it was worth branching off this discussion into a new post.
At one level the position is understandable, reducing seats was how historically devolution used to work with a reduction in Irish seats when home rule was introduced in 1921. The idea that seat allocation was related to national status received more systematic backing at the 1944 Speaker's Convention where the principle was agreed that there was a case for "substantial representation" of a separate nation beyond what mathematical divisions would provide.
However now the principle of electoral equality has completely swept this approach away.
To trace the most official examples, the idea of reducing Scottish and Welsh seats pops up several times in the Justice Committee Report "Devolution: A Decade On" and the most precise formulation is cited from a Constitution Unit Report by Robert Hazell: "Towards a New Constitutional Settlement: An Agenda for Gordon Brown’s First 100 Days and Beyond":
One partial solution Gordon Brown could consider is to harmonise the electoral quotas of the four UK territories, ending English under-representation, or even to reduce the representation of Scotland, Wales and Northern Ireland to two-thirds that of England*.
*This solution has historic precedent in that during the operation of the Northern Ireland Parliament (1922-72) Northern Ireland had 12 MPs, rather than the 18 its population demanded.
The Justice Committee Report is a little sly in this respect, reframing this as:
The latter approach was taken when the 1922 Parliament of Northern Ireland was created, and Northern Ireland MPs were reduced to twelve. In 2005 the number of Scottish MPs was reduced from 72 to 59. (pp. 61-62)
The implication being that the 2005 reduction is another example of the principle at work in the Northern Ireland example when it's actually just a delayed consequence of the Scotland Act 1998, which I'd argue is working under quite different principles.
Now in a crude way the Act could be seen as being a 'seats for powers' transaction as it both create a devolved body and decreases seats (that link is made pretty explicitly by that piece in the Scotsman), but the method it uses to do so is significant.
The reduction in seats removes the minimum of 71 seats and a separate Scottish quota, ending over-representation of Scotland - but the method used more represents a principle of electoral equality by syncing the Scottish electoral quota with the English quota, something that was repeated and taken further with` the creation of a UK-wide quota <http://www.legislation.gov.uk/ukpga/2011/1/part/2>`__ by the Parliamentary Voting System and Constituencies Act 2011.
The trend through these changes has been an effective reduction of seats in devolved regions (or will be if the current boundary proposals are ever passed), but the justifying principle in these cases was "one person, one vote" not "seats for powers". Each successive change has been in favour of greater and stricter stress being giving to mathematical equality on constituency apportionment, so to at this point give Scotland less representation because of greater devolution would be a step backwards.
Although there's historical precedent it's worth considering that how we understand seats and apportionment has undergone enormous shifts since 1921. Today the idea that national representation should be considered is completely lacking from the law governing apportionment. It's also not at all clear it resolves the problems it's supposed to address. Is the West Lothian question really resolved by slightly fewer Scottish MPs voting on English matters? Similarly, on matters like defence and foreign affairs, there's no particular reason why Scottish voices should matter less on the issues they would still return MPs on.
As a compromise to save the union it could be a short-lived one. In answer to a question on his presentation at the Constitution Unit Alan Trench put forward that devo-max might be an unstable position as foreign policy can often be a wedge issue - would this situation be better or worse if Scotland had a legitimate grievance of unequal representation in crafting that policy added to it?
But on the practical side assuming an 'English votes on English issues' rule, Scottish MPs would be left with far less to do (especially if their ability to sit on committees is restricted) and their non-voting functions probably could be done by fewer MPs. If so reducing their number would seem to be a good idea not only to avoid waste, but to ensure the job is still active enough to attract good candidates. But how can this be done while still respecting voter equality?
The solution is to separate the idea of an MP's vote from their physical person. Scottish voters are entitled to have their votes weighed the same as those in the other nations - but Scottish MPs don't need to have the same voting power as other MPs. The voting power of Scottish MPs could be increased to allow both a reduction in numbers and also preserve mathematical equality (for a reduction of 2/3 this would give Scottish MPs a vote worth one and a half their current vote, and so on).
Weighted voting isn't a new idea in principle but it's one that's rarely been used in the UK - I think it's a good one to think more about in this case as it allows respect for both voter equality and the fact that more devolution will have practical effects at Westminster.