Scottish Secretary David Mundell suggested Boris Johnson’s decision to campaign to leave the European Union would have little impact as he confirmed he backs staying in.

Scotland’s only Tory MP also compared the arguments surrounding the EU referendum to those around Scottish independence.

“My reasons for supporting us staying in are not that different from the Scottish independence referendum,” he said.

“These people who are proposing change have to set out what the alternative would look like.

“I don’t believe that the have done so.”

He added: “I don’t love the EU.

“But I’m not prepared to recommend to people to leave without what it would mean for them.

“What it would mean for real people, for their jobs, for their families, for their security?

“These are the things that people need to know if they are going to go for this big change. “ He added that Out supporters “have not set out what the alternative would look like. And I don’t see any prospect of them doing so. It is completely uncertain.”

On Mr Johnson’s decision, he said: “I think it will have absolutely zero impact in Scotland.

“I don’t think he resonates with voters in Scotland.”

He went on to question the effect it would have overall, saying: “I don’t think this will be a personality-based campaign. I think this is going to be a debate about the issues.”

He praised the deal that Mr Cameron secured in Brussels last week, including an up to 7-year ‘emergency brake’ on migrant benefits.

Mr Mundell said: “I think it was the best deal that was available in the circumstances. When you are in a club with 27 other members you are not going to be able to get everything you want.”