Few things are certain in this election, but the presence of a lot more SNP members in the next parliament looks pretty much guaranteed. So far the significance of this change has been discussed exclusively in terms of the balance of power on the floor of the Commons – the capacity to support a Labour government or obstruct a Tory one. That is certainly the first and the biggest impact a regiment of Scottish nationalists would have.

But it isn’t the only one.



Parliamentary authorities are, I’m told, scratching their heads wondering about all the other bits of the legislature that will be affected by an SNP surge. Take select committees, for example. Control of the chair is allocated to parties using a formula based on the number of seats they win, with some discretion enjoyed by the Speaker. There are some conventions that dictate who gets what: the main opposition usually has public accounts; the government gets Treasury. But much of the rest is settled through “the usual channels” – the informal deal-making process between whips’ offices.

How the “usual channels” work in practice is one of the most opaque features of British politics – a mysterious stash of legislative WD40 that lubricates the wheels of parliament in all kinds of sticky situations. It is the most Westminstery institution in Westminster and no one is quite sure how the SNP will play that game – if indeed they choose to play at all.

In the last parliament they had six MPs; in the next one they could have as many as 50. That would, presumably, entitle them to an allocation of select committee posts equivalent to the Lib Dems’ former tally (including two chairs – currently justice and international development). But what policy areas are appropriate for a party that represents a devolved nation?

The Lib Dem whips might even be evicted from their premier league offices by the members’ lobby and banished to a broom cupboard upstairs, which may sound like a minor inconvenience but would be a significant demotion in parliamentary authority. A lot of power and status is settled by office geography in the Palace of Westminster.

These are, of course, secondary considerations to the bigger matter of passing legislation in the Commons chamber. But the issues are intertwined. The Conservatives are currently campaigning on the premise that Scottish nationalists would be second-class MPs with no legitimate mandate to decide what happens in England. But that isn’t how parliament works and it isn’t how the Tories would have to behave in practice.

All the tools of legislative influence, mischief-making and subterfuge – ambushing amendments, private members’ bills, filibusters and the rest – would be as available to the new Scottish cohort as to anyone else. To manage that threat, the “usual channels” would have to be open. In other words, a Tory-led government would have no choice but to find a way of doing business with the SNP.

It is also worth noting in this context that the Speaker’s role will be greatly enhanced in a parliament as hung as the next one looks likely to be. In which case, the Conservatives will pay a price for dedicating the last day of the last session to a botched coup against John Bercow. The first weeks of the next parliament will be all about making friends and influencing people in the corridors of Westminster. The Tories may come to regret working so hard to foster alienation and enmity.