A difficult day. For Humza Yousaf, leader of the Scottish National Party and First Minister of Scotland.

A difficult day. For Humza Yousaf, arguably a casualty of circumstance, fighting a battle with few weapons immediately to hand.

A difficult day. For the SNP’s former chief executive, Peter Murrell, arrested and questioned by police about party finance.

A difficult day for Mr Murrell’s wife, Nicola Sturgeon.

A difficult day, says Mr Yousaf.

Either he is icily calm. Or that was ironic understatement. Or simply words in a crisis.

Let us be clear about one thing. Mr Murrell may have cogent and consistent answers to those police questions. However, optics also matter in politics. The look, the image, the appearance.

Right now, the optics for the SNP are somewhat sub-prime.

Police officers searched the Glasgow home shared by Mr Murrell and Ms Sturgeon. Over two days. With curtains and blinds drawn. Not a good look.

In the garden stood a large blue and white police tent, covering a van. Which presumably held material gathered in the search. Not a good look.

At SNP headquarters in Edinburgh, more officers conducted searches. They were seen carrying green packing crates out of the building. Not a good look.

The police operation appeared extensive and thorough; perhaps to demonstrate that nobody lies beyond the reach of the judicial process. Not a good look for those on the receiving end.

To be clear, again, the SNP stressed full co-operation with the police investigation first launched in July 2021 after complaints over the use of money donated to assist the independence cause in an anticipated referendum. Still not a good look.

Those complaints were accompanied by grumblings about “top-down leadership” in the party, about a lack of consultation. At the time, such complaints were occasionally discounted as emerging from the usual suspects.

There is a degree of truth in that. Some of the irritation arose from thwarted ambition or from the personality clashes which are far from unknown in politics. Such is often the case where power is unevenly shared, where the ousted or disregarded feel their views are ignored.

However, Humza Yousaf cannot afford to pursue such responses.

He cannot ignore the disquiet about internal party finances which led Douglas Chapman to resign as treasurer in July 2021, complaining that he was being denied information.

If Humza Yousaf is to survive, let alone thrive, as leader, he now needs a complete break from the immediate past in his party.

It is continuity no more.

Self-evidently, Mr Yousaf can do nothing about the police investigation nor about any deliberations which may follow within the Crown Office and Procurator Fiscal Service. That is why I said he is now, to some extent, a casualty of circumstances which he did not, himself, create. Not his doing, directly, yet he may take the political hit.

Entirely reasonably – and I intend that without a hint of irony – the SNP’s chief opponents are seeking to bind Humza Yousaf into the internal controversy which is now assailing the SNP.

Douglas Ross, who leads the Scottish Conservatives, said it was “crucial” that those at the top of the SNP co-operate fully. He named Ms Sturgeon – and Mr Yousaf.

For Labour, Anas Sarwar said there were “huge questions” for the SNP to answer. Again, he specified Ms Sturgeon and Mr Yousaf.

In essence, their argument will be that the new FM turned a blind eye in the past to internal SNP problems.

To repeat, these are legitimate challenges. Humza Yousaf is now SNP leader and our First Minister. He should indeed explain what he knew about internal party arrangements. Further, he should set out his intentions for the future. I know it will be difficult to promulgate advance plans in the middle of what is a catatonic shock for the party he leads.

However, I believe we can already see the emergence of a tripartite strategy.

Firstly, he must cut loose from Nicola Sturgeon, at least in the interim. He must, in effect, disown her, for now. In that regard, it may help that Ms Sturgeon will be familiar with the tactic. She did the same with regard to her own predecessor, albeit in different circumstances.

It also helps that Ms Sturgeon is certain to maintain a low profile for the immediate future. For example, she cancelled a public Edinburgh appearance this week.

In practice, the disowning strategy is already firmly under way.

Mr Yousaf proclaimed his dissatisfaction with the way party organisation had been handled. No ifs or buts. This was, partly, aimed at the former chief executive, Mr Murrell. But it was also, of course, directed towards Ms Sturgeon, the former party leader.

As if to emphasise the concept of change, these pronouncements were made in Bute House, the official residence of the First Minister. A reminder of where power now lies.

Secondly, he must turn that statement of dissatisfaction into a programme of internal party reform. Again, that process is under way. The party’s NEC is undertaking a review of governance and transparency. Without pre-empting that, Mr Yousaf has stressed the need for the SNP treasurer to access all accounts.

Asked if he felt that it was wrong for the top two posts in the SNP to be held by a married couple, Mr Yousaf noted, drily, that his wife would not be applying for the vacant job of chief executive.

Thirdly, he needs public engagement – and soon. He needs to get back, swiftly, to the daily issues which beset our people, most notably the economy and the cost of living.

On that “difficult day”, the Scottish Government detected “encouraging signs” for the tourism industry and set out ministerial thoughts on health and the economy. Most significantly, the deputy First Minister Shona Robison confirmed that new Scottish income tax rates are in operation, pegging back the revenue taken from lower earners while increasing the levy from the higher paid.

This remains fiscally contentious. But it gives Mr Yousaf a redistribution narrative. One that he will be keen to repeat. If, that is, he can get a hearing over the cacophonous noise created by his own party’s internal crisis.