Prime Minister David Cameron has launched a defence of the United Kingdom as his government prepares to put the "facts" about Scottish independence to the public.
While people in Scotland will make the decision in autumn next year, the implications will have obvious impacts across England, Wales and Northern Ireland, the Conservative leader said.
"Britain is admired around the world as a source of prosperity, power and security," he said.
"Those glorious Olympics last summer reminded us just what we were capable of when we pull together: Scottish, English, Welsh, Northern Irish, all in the same boat - sometimes literally.
"If you told many people watching those Olympics around the world that we were going to erect barriers between our people, they'd probably be baffled. Put simply: Britain works. Britain works well. Why break it?"
Addressing matters of the "heart and head", Mr Cameron spoke out one day before the British Government publishes the first in a series of analysis papers about Scotland's role in the union. It comes one week after the Scottish Government published a "road map" from the referendum next year to full statehood in early 2016.
Mr Cameron said Britain has built up "world-renowned" institutions such as the NHS and BBC, and "fought for freedom" in two world wars, leaving "unbreakable bonds".
He said: "But the case for the UK is about head as well as heart - our future as well as our past.
"I have no time for those who say there is no way Scotland could go it alone. I know first-hand the contribution Scotland and Scots make to Britain's success - so for me there's no question about whether Scotland could be an independent nation.
"The real question is whether it should - whether Scotland is stronger, safer, richer and fairer within our United Kingdom or outside it. And here, I believe, the answer is clear."