Why does no one doubt the unity of Canada?

It was further reported that the Prime Minister believed that if Scotland wanted any further devolution of powers it would have to back independence.  

As a unionist reading such comments, I wondered whether the Prime Minister wasn’t playing a role in the nationalists’ campaign.  Not only are the Conservatives in danger of being out of step with the majority of Scots, opinion polls continually indicate growing support for a middle option which would substantially extend devolution, while stopping short of independence, but  comments suggesting a unified tax and benefits system are essential to a single country are just plain wrong.