BBC journalist was booed after asking a question about Scottish independence at the SNP’s Westminster campaign launch.

James Cook, asking the first question given to the media following John Swinney’s speech at the event in Glasgow, asked the First Minister: “You said that leaving a 50-year-old union with the EU has wiped billions from the economy. Why would leaving a 300-year-old union with England not be even worse?”

The question led to boos and some laughter from the crowd of assembled activists (below) before Swinney interjected.

“Now, before we go any further. I just said I believe in open debate and respectful disagreement,” the SNP leader said.

“So for this bit of the gathering, no questions are to be applauded or heckled. And none of my answers are to be applauded or heckled.”

Swinney then asked Cook to repeat his question, and then answered: “What independence enables us to do is to take decisions that are important and relevant to enhancing the lives of people in Scotland.

“And part of that involves taking sensible decisions about how you cooperate with your neighbours.”

The moment drew the ire of some of the assembled journalists including The Guardian’s Libby Brooks, who called it an “ugly moment”.