RBS would still move its official headquarters out of Scotland should the country quit the UK to avoid Brexit, the bank's chief executive has confirmed.

Reigniting a row the erupted in the days before the 2014 independence referendum when RBS said it would switch its registered headquarters from Edinburgh to London in the event of a Yes vote, Ross McEwan claimed the business would remain "too big for the economy" in an independent Scotland.

He also warned Nicola Sturgeon to consider potential uncertainty for the economy that calling a new referendum could provoke when deciding whether to move for a repeat vote.

Some experts have said Scotland's financial services sector could benefit if the country was to leave the UK and retain its relationship with Brussels, following a independence referendum the Nicola Sturgeon has said is "highly likely" to call after June's EU referendum result.

However, Mr McEwan said the position was unchanged despite the Brexit vote, although he emphasised that the change would be an administrative exercise over shifting a "plaque" and have no impact on the 12,000 bank employees north of the border.

Asked about the bank's reaction should Scotland vote to leave the UK, he said: "We'd have to make the same moves I suspect because the Royal Bank of Scotland, being domiciled in Scotland, would just be too big for the economy, even in the shape that we're building.

"That's around the plaque, it's not about where our people are because we have a very big business up here in Scotland.

"I've got 12,000 people who serve both the Scottish people and we also run our retail business from up here along with a lot of our technology.

"Two years ago when we had the Scottish referendum, I made it very clear we'd have the people in the right place, that moving the plaque didn't make any difference to them.

"I think that would be the same. I think for any country, they just need to remain very competitive so businesses like ourselves want to operate in those countries."

Asked what he would say to Ms Sturgeon if she wanted his views on the economic impact of a second independence vote, he replied: "Just take account of uncertainty - that's what you're seeing after Brexit.

"It's uncertainty that slows markets down. Make sure the long game's worth it. But that's going to be up to the people of Scotland."

The Scottish Government played down the significance of Mr McEwan's comments, saying he had been clear that the location of the brass plaque would have "no impact" on jobs.

A spokeswoman added: "The uncertainty our economy faces is from Brexit. That's why our immediate priority is to secure our continued place in the single market and maintaining and strengthening our links with our key European markets."

However, Scottish Labour said the intervention showed that Scotland is well served by being in the UK, and reiterated its opposition to another referendum on independence.

Ms Sturgeon has said she is examining all options to protect Scotland's relationship with Europe following the EU referendum, which saw 62 per cent vote remain north of the border but the leave side win UK-wide.

Scottish Labour's business manager, James Kelly, said: "Only the SNP could claim a bank leaving Scotland as some sort of victory.

"This intervention once again makes clear that being part of the UK is good for jobs, business and the economy in Scotland.

"We don't need to risk all that with another referendum on independence. Labour committed in our manifesto to vote against a second independence referendum in the lifetime of this parliament. That position won't change any time soon.

"We have been pleased to give Nicola Sturgeon our full support to negotiate with the UK Government and EU institutions to find the best deal for the people of Scotland.

"Two mandates have to be respected - people voted in overwhelming numbers to maintain our relationship with both the EU and the UK. Delivering an outcome that achieves that is critically important."