David Cameron has admitted he "contemplated having to go" if Scotland voted for independence.
The Prime Minister said he would have been "heartbroken" by the break-up of the UK and considered his position when polls put the Yes campaign ahead just days before the referendum.
It is only a matter of time before Scotland becomes an independent nation, Alex Salmond has suggested.
The First Minister, who this week announced his intention to resign from his post, said the majority of younger Scots supported independence.
He told Sky News' Murnaghan programme: "When you have a situation where the majority of a country up to the age of 55 is already voting for independence, I think the writing's on the wall for Westminster."
"I think the destination is pretty certain, we're only now debating the timescale and the method," the SNP leader added.
The woman expected to replace Salmond said she will "follow the mood of the people" if promises made in the run up to the vote are not met.
The double Grand Slam winner said he did not regret giving his opinion, but was 'disappointed' at the way he went about it.
Alex Salmond has announced his intention to end a 24-year career at the forefront of Scottish politics. Here is a brief look at his career.