Why a logjam in the Lords may be catching Holyrood's attention

The logjam in the Lords just got more jammed.

In addition to the vast amount of detailed scrutiny already cramming the agenda in the Lords, the Scotland Bill is back. Its first day of Committee Stage consideration (the first of five days) will be on the 26 January. This is a Thursday - a day normally reserved for debates rather than legislation. It's a measure of the congestion in the Upper House that debates initiated by one of the parties, by an individual peer or by a select committee are being pushed aside to get assorted mega-bills through.

And the other point about Thursdays is that Scottish peers often head home - and now they may feel obliged to stay.

Hammering through the Welfare Reform Bill, the Legal Aid etc Bill, the Health and Social Care Bill and the Protection of Freedoms Bill was difficult enough before the resurfacing of the Scotland Bill. Now the timetable is so tight that no delay or slippage can be brooked by Coalition business managers. The end of the parliamentary year is looming and they do not want to find themselves forced to choose between losing a major bill (because they can't pass it in time) or gutting it in the face of delaying tactics.

And the Scotland Bill simply poses more problems. The bill offered the Scottish Parliament more financial and tax-raising powers, and would effectively create a Scottish income tax. But it has come in for heavy criticisms from all kinds of heavyweight figures in the Lords - former Scottish Secretaries like Lords Laing and Forsyth, Lord Barnett, the author of the fabled "Barnett Formula" which controls the division of funding between the nations of the UK, and various heavy metal Scottish Labour peers who regard it as ceding too much ground to nationalism. Between them they have the parliamentary nous to tie the bill up for quite a while, should they decide to do so.

And nor is the bill much to the SNP's liking. They wanted more extensive tax and borrowing powers.

But the biggest flashpoint may be the new element which looks likely to be added - legislation around the conduct of the promised referendum on Scottish independence. The timing, the exact question and the supervision of the referendum are all at issue - many Westminster politicians suspect that the wily SNP First Minister, Alex Salmond, will configure the referendum to his maximum advantage, unless they stop him. The SNP will not be able to take any direct part in these debates in the Lords, because the party has never been prepared to nominate peers - but their voice will certainly be made manifest when (if...) the bill comes back to the Commons.

And they have another trump card. Normally Westminster legislation affecting Scotland has to be approved by the Scottish parliament via what is known as a Legislative Consent Motion.

If the SNP majority in Holyrood don't like the bill in its final form, they have the power to strike it down, and it would be a huge step for the UK Parliament to over-ride their will.