Through the legal looking glass?

@TobyMasonBBC here with a look at the latest devolved constitutional conundrum coming our way this afternoon.

In another post just under a month ago I speculated whether Mick Antoniw's Asbestos Bill could well be heading for the Supreme Court to decide whether it's lawful.

This afternoon, AMs will be asked whether another Bill - this one close to a racing certainty to face a challenge - should be allowed to be rushed through the Assembly in just three weeks, the first time such a process will have been used.

The Agricultural Sector (Wales) Bill hasn't been formally published yet - but it's aimed at replacing the functions of the now-defunct Agricultural Wages Board for England and Wales. The role of the AWB was to set the wages and conditions of agricultural workers - their current provisions run out this October. You can read the background from last week when the Emergency Bill was first mooted here.

The Welsh Government's argument is that in order to preserve uninterrupted the wages and conditions of the estimated 13,000 workers in Wales who are covered, they need the law changed before the summer recess - hence the truncated lawmaking process. The Bill would effectively give Welsh ministers the powers to set those wages and conditions.

It's called the Agriculture Bill. The National Assembly has powers over agriculture - so what's the problem?

Lots. Because it's a very open question indeed as to whether this bill is about agriculture, or instead actually about employment - which isn't devolved.

As the Presiding Officer puts it in her note to AMs ahead of this afternoon's vote:

The issue is therefore what is the purpose of the Bill? Is it to ensure a successful agricultural sector, or to safeguard the wages and conditions of agricultural workers?

She makes it clear that she is still considering whether to rule the Bill within competence. And reading her note, it's clear that the Assembly Commission have at least equal concerns about the legality of this legislation as they have about the Asbestos Bill.

If the Assembly votes in favour of the emergency legislative process later then, as with all Bills introduced, the Presiding Officer, as head of the Commission will need to certify the Bill as being within the Assembly's powers by next Tuesday.

The odds are she probably will - but with public caveats, as with the Asbestos Bill.

What if the Presiding Officer declines to certify the Bill as being within scope? My reading of the Government of Wales Act suggests it could still continue its progress through the Assembly if the government can muster a majority at each stage. But we'd surely be through the looking glass in which case? How would Rosemary Butler phrase it in the chamber? "I now call on the Minister to propose the Bill...which incidentally I don't believe to be legal...but anyway, Minister..."

Incidentally, it's a happy coincidence that for the next three weeks at least, the Welsh Government has a one seat majority in the Assembly due to Ieuan Wyn Jones' resignation as the AM for Ynys Mon, with the byelection due to be held a couple of weeks after the end of the Assembly's summer term.

The UK Government maintains that the AWB was, and is, an employment, not an agriculture issue and not devolved - therefore it's highly likely the Attorney General would exercise his constitutional prerogative to refer it to the Supreme Court if and when it's passed. The Welsh Government are equally clear that it does come within the Assembly's powers.

Another legal tussle in front of the highest court in the land wouldn't be a particularly welcome development for either side. On the other hand, with the Welsh Government pushing hard for a change from the current conferred powers model to one of reserved powers, as in Scotland and Northern Ireland, and the Secretary of State having voiced his opposition to such a move last week, perhaps Welsh ministers wouldn't be too distraught to have another high profile legal wrangle in the headlines.