Scottish referendum: From empire vanguard to independence?

We could be on the brink of the end of the United Kingdom as we know it.

It is fair to say that Britannia no longer rules the waves - and hasn't for many decades - but what might independence for Scotland mean in years to come?

And how did Scotland go from being at the vanguard of the spread of the British Empire to the verge of independence?

Emily Maitlis reports for BBC Newsnight.