ALEX Salmond has accused Prince William of "poor judgment" after he met Gordon Brown to discuss independence, and said it would be "extraordinarily foolish" to get dragged into the constitutional debate.

The Alba Party leader questioned “what on earth Prince William thought he was doing” by meeting the former Labour Prime Minister to discuss independence last week.

He said the Royals should beware “desperate unionists” out to use them for political ends.

The former First Minister also said Yes supporters should "read the tea leaves" and gear up for Indyref2, as the Unionist side was already doing it.

The Prince and Kate met the former Labour Prime Minister and his Sarah at Holyroodhouse last Thursday in a meeting which was given no advance publicity.

It came just days after Mr Brown relaunched his Our Scottish Future thinktank as a pro-Union campaign movement.

READ MORE: Gordon Brown launches pro-Union campaign aimed at 'middle Scotland'

Kensington Palace later confirmed the Prince had been listening to views on independence from different communities.

In a new video to Alba members, Mr Salmond said: “What on earth Prince William thought he was doing having a confab with Gordon Brown, just as Gordon set up his last campaign for the Union...

“We’d be foolish indeed not to read the tea leaves in this sort of thing.

"In the run up to 2014, largely because I saw the argument for continuity of social institutions in these islands, we were extremely keen to keep the monarchy, the head of state, out of politics.

“I think the Queen has done a marvellous job and a lifetime of service.

“We should have no hesitation about seeing in that meeting with Gordon Brown what seems to be the preparations for doing what is absolutely extraordinary, which is to have a constitutional monarchy looking at and directly discussing aspects of the constitutional debate which should of course be left to the people. 

“It would be enormously wise of the Royal Family to follow what has been the Queen’s example over her long reign, as to keep the monarchy over and above politics.

“It does seem extraordinarily foolish to have a situation where it can even be said that the monarchy, the future head of state, is involved in the Scottish constitutional debate.”

He added: “Back in 2014 David Cameron made a last ditch desperate and failed attempt to drag the Queen into politics.

"The Brown meeting shows poor judgment on both sides but the same degree of unscrupulous unionist desperation.

"The independence team should take note.

“It is quite clear that the forces of the union, David Cameron previously, and now Gordon Brown, have no compunction in getting themselves ready and set for what is coming in the next referendum campaign.

"However, the Scottish Parliament elections have left them in a state of disarray.

"That is why the case for Scottish independence must be progressed now as a matter of urgency.

"The Tories at Westminster are surprised that they are not already facing a renewed constitutional challenge and are wondering what on earth is going on.

"It would be infinitely better for the independence side to seize the moment and strike when the iron is hot to progress the constitutional issue."

Mr Salmond also announced that Alba had been forced to reschedule its first annual conference because of a higher than expected attendance.

The two day event had due to open on September 18, which Mr Salmond had called an “auspicious day”, despite it being the anniversary of the No vote in 2014.

He said the conference was now likely to be in a bigger venue a week earlier.

Mr Salmond, whose party polled 1.7 per cent in the Holyrood election, also announced a series of “interim” appointments pending conference.

Chris McEleny will be Alba general secretary, Lynne Anderson and Caroline McAllister will coordinate the 13-strong Alba councillor group, and former MP Corri Wilson will be membership convener. 

Mr McEleny said: “Alba is Scotland’s newest and fastest growing political party. Our membership numbers are rising week on week since the Scots Parliament elections.

“Alba can make a valuable contribution to the independence case, particularly in ensuring it is put forward with immediacy, strength and determination. 

“We are all excited about the prospect of building a new party which will abide by our aspiration of living in the early days of a better nation.”