Boris Johnson said a second independence poll is not a priority for the UK Government.
The Prime Minister also insisted a second independence poll is not a priority for the UK Government.
Speaking in the House of Commons, Conservative MP Brendan Clarke-Smith (Bassetlaw) claimed Scottish nationalists would cut defence spending and “unilaterally disarm” if they achieved independence.
Mr Johnson replied: “The Scottish contribution to our armed services is immense, everybody knows it, it’s a fantastic thing, it helps to make the UK what it is.
“It would be utterly tragic for the whole world if the UK armed services were to face a division of that kind or a loss of that kind.”
Scottish First Minister Nicola Sturgeon has outlined plans to hold a second vote on Scottish independence on October 19 next year.
With the UK Government refusing to grant consent for such a ballot, Ms Sturgeon is asking Supreme Court judges to rule if Holyrood can hold a referendum without the backing of Westminster.
Alba MP Neale Hanvey earlier accused the UK Government of holding Scotland’s democracy “hostage”.
Mr Hanvey (Kirkcaldy and Cowdenbeath) said: “I listened carefully to the Prime Minister’s warm words about the Commonwealth and the relationship between independent countries, and, of course, in 1941 it was then prime minister Churchill that signed the Atlantic Charter with the United States, committing both Britain and the United States to delivering people’s right to choose their own form of government and self-government.
“This respect for the principle of equal rights and self-determination of peoples was incorporated into the United Nations charter in paragraph two of articles 173 and 76.
“In light of this, can the Prime Minister set out what mandate he has won which allows him to breach this UN principle, deny Scotland’s claim of right and hold Scotland’s democracy hostage?”
Mr Johnson replied: “I know that the First Minister has asked for another referendum. I just point out that we had one in 2014.
“I think right now the priorities of the country should be rebuilding after Covid. They should be taking us forward together as a united country, and that’s what we want to do.”