THE SNP has said it has an “open ear” to a potential second referendum on the UK’s membership of the European Union, while continuing to fall short of backing one outright.

Ian Blackford, the party’s Westminster leader, insisted its priority was making sure Scotland could stay in the single market and customs union, but added it was "watching developments" over the prospect of another EU vote.

He said a hard Brexit would signal a "clear road map towards a second independence referendum that for me would be the priority".

It comes as SNP Brexit minister Michael Russell said he was “absolutely not hostile” to a second vote on any future deal, but suggested the result in Scotland would need to be respected.

He told the BBC: “There will have to be a vote at some stage. The question is what vote and when, and how it’s going to be achieved, and presently we don’t have answers to that.”

Mr Blackford said the SNP was not “in all circumstances diametrically opposed” to a further referendum, adding: “We have an open ear to developments on that front, but for us it's the priority of staying in the single market and the customs union that's most important."

He argued that if the UK Government did not listen to the SNP's "power grab" concerns over its Brexit legislation, then an independence vote could follow and the Scottish Government had a mandate.

He said: "What I'm seeking to do is to defend the rights of the Scottish people and the powers that they have in their parliament, that is the immediate priority for us.

"Of course I would make the point that if we cannot get the UK Government to listen on this then ultimately we will be having a discussion with the people of Scotland as to how we best protect our parliament, I would argue that independence is the best way of doing that."

He added: "We're not at the moment talking about a timing of an independence referendum, what we have said is that we'll make a judgment on that once we've got to the end of the Brexit process, so we'll concentrate on making sure we're standing up for our rights through the Brexit process.

"We will have that debate with the people of Scotland and the economic future of Scotland, but we will only come back to a discussion on the timing of a referendum once we've got through the Brexit process."

As Theresa May narrowly won another crunch vote on the Government's European Union (Withdrawal) Bill last week, Mr Blackford branded the Prime Minister "very weak", adding "at some point that luck will run out".