The First Minister has been challenged on why the SNP's 35 MPs abstained on a Commons motion calling for a customs union with the EU.

Nicola Sturgeon said stopping Brexit altogether is her party's "top priority" after her MPs opted not to vote on Tory MP Ken Clarke's proposal during Wednesday's indicative votes.

Clarke's motion called for a UK-wide customs union with Brussels as part of a withdrawal agreement and was only defeated by eight votes, with 264 votes for but 272 against.

Speaking at First Minister's Questions on Thursday, interim Scottish Conservative leader Jackson Carlaw challenged the FM on her party's decision.

The SNP has long argued in favour of a "soft Brexit", which would mean the UK staying within both the customs union and the European single market.

Carlaw accused Sturgeon of attempting to stoke up "faux outrage" and "grievance" in order to pursue Scottish independence.

He told MSPs: "When it came to the crunch the First Minister whipped her MPs against supporting her own policy of a customs union."

"Isn't it the case that what Scotland saw yet again yesterday is that when push comes to shove for the SNP, it's not about finding a solution to Brexit, it's about pursuing their independence obsession?"

The First Minister replied: "For two long years when stopping Brexit didn't seem possible the SNP argued for a single market-customs union membership compromise.

"That was ignored by the Tories and indeed everybody else.

"Now that option , which I think is the minimum you would need to protect Scotland's interests, wasn't actually on the ballot paper last night.

"That said, over the next few days we will continue to work across Parliament for a compromise of that nature, if that proves to be the only alternative to a hard Brexit."

But she added: "This whole process, thanks to the Tories, is now such a mess that stopping Brexit altogether must be our top priority.

"Moreover, that is now possible. Actually, the highest number of votes cast in the House of Commons last night was for the People's Vote."

Sturgeon was referring to a motion by Labour's Margaret Beckett calling for a "confirmatory public vote" on Theresa May's Brexit deal, which won 268 votes but was rejected by 295.

Both the Beckett and Clarke motions achieved greater Commons support than Theresa May's Brexit agreement, which only won 242 votes in March 12's second "meaningful vote".

The First Minister ridiculed the Prime Minister's offer to resign to help finally pass her deal, which the UK Government wants to table for a third time in the coming days.

Sturgeon said: "Theresa May must be the only leader in living memory who has tried to fall on her own sword and has managed to miss."

On the indicative votes, Carlaw told the SNP leader: "For the avoidance of doubt, no-deal was rejected, a second referendum was rejected again, revoking Article 50 was rejected.

"Yesterday, when it came to the crunch, the First Minister whipped her MPs against supporting her own policy of a customs union and single market membership and that was defeated too.

"Surely it is time to back the deal and get on with it."