Andrea Leadsom has opened the door to the potential break-up of the UK, revealing she would “never say never” to a second Scottish independence referendum if she became prime minister.

The Tory leadership candidate made clear that while she was personally opposed to another independence vote, she also believes in Scotland’s devolution settlement and its sovereignty and so the issue “would be up for negotiation”.

Scotland voted 55-45% in favour of staying in the UK in 2014.

But the country heavily backed Remain in the 2016 Brexit referendum and First Minister Nicola Sturgeon has published legislation which could pave the way for another independence vote aimed eventually at keeping Scotland in the EU.

Theresa May used the UK government’s powers to reject Sturgeon’s calls for a second independence referendum in 2016, insisting “now is not the time”.

But Leadsom, one of the rank outsiders in the Tory leadership contest, told a Westminster lunch she could not rule it out.

“I think the Scottish nationalists should actually be spending their time sorting out some of the challenges that there are in Scotland around healthcare, infrastructure, broadband rollout and so on,” she said.

“So I think it would be very helpful if they would stop that complete focus on independence at the expense of everything else.

“But in reality all of these things would be up for negotiation.

“I do believe in sovereignty, I do not believe that Scotland should have another independence referendum right now, I don’t think most people in Scotland would want that to happen.

“But I would never say never.”

Leadsom went on: “The reason I say never say never is because I do not think that there should be another independence referendum in Scotland, I do not think it’s in their interests, but on the other hand I am a big believer in devolution.

“So what I just want to say is I’m not going to stand here and utterly rule it out because I think that is disrespectful, but I would very strongly fight against a second referendum which I don’t think is in the interests of Scotland and it’s definitely not in the interests of the United Kingdom.”

Her comments came as Sturgeon visited Brussels to hold talks with EU chief Brexit negotiator Michel Barnier and European Commission president Jean-Claude Juncker, to make clear that Scotland wants to stay in the bloc.

Following talks with Barnier, Sturgeon told the European Policy Centre think tank: “The people of Scotland have to have a choice before it’s too late to stop the damage of Brexit being done.

“Increasingly, Scotland and the UK are on different political paths. We have to confront whether the better response to that is to have the ability to be independent and shape our own future.”