The future of the UK would come under "very real threat" if it leaves the EU against the majority wish in Scotland, a Northern Ireland Office minister has warned.
Ben Wallace was being questioned on the potential implications of a Brexit by a Westminster committee.
Giving evidence to the Northern Ireland Affairs Committee, he was questioned about Sinn Fein's insistence that a poll on the reunification of Ireland should be called if the UK leaves but the people north of the border vote to remain.
The Conservative MP insisted the decision to trigger a border poll rested solely with the Government, but he went on to warn of the implications for the UK if Scotland voted to remain but the overall vote was to leave.
"It is my belief that should the United Kingdom vote to leave but Scotland vote to remain I do believe there is a very real threat that the United Kingdom would then break up, certainly Scotland would leave the rest of the United Kingdom," he said.
Mr Wallace said such an outcome would "embolden" the Scottish National Party to press for another independence referendum.
"I love the United Kingdom, I want to remain the United Kingdom, including Northern Ireland in that, and therefore one of the major factors that weighed in my mind about why we should remain in the European Union is because I want the United Kingdom to stay together," he said.
He added: "I am a unionist, I want to safeguard the United Kingdom, I don't want to put that at risk.
"I believe the risk increases if we leave."
The committee is currently assessing the potential impact of a Brexit on Northern Ireland.
Mr Wallace addressed a range of issues during almost two hours of questioning at Westminster. While he is firmly in the 'remain' camp, Northern Ireland Secretary Theresa Villiers is a high-profile advocate of the 'leave' campaign.
While Mr Wallace insisted a Brexit would make trade with the Republic more difficult, he rejected any suggestion that the peace process could be put at risk if the UK exited the EU.