
Everyone quotes them, most people get them wrong. Here is what they actually said, word for word.
From her memoirs The Downing Street Years (1993) page 624:
"As a nation, they [the Scots] have an undoubted right to national self-determination; thus far they have exercised that right by joining and remaining in the Union. Should they determine on independence no English party or politician would stand in their way."
That is the origin of the phrase. She was saying Scotland's right to leave is recognised, but she opposed devolution as a half-way house.
As Prime Minister, Foreword to Scotland in the Union 1993:
"No nation could be held irrevocably in a Union against its will"
b) Later, Ditchley Foundation Lecture 9 July 2011:
"My own view on Scottish independence is very straightforward: it would be folly - bad for Scotland and bad for England - but, if Scots insist on it, England cannot - and should not - deny them."
That second one is often paraphrased as "who is England to stand in their way."
It was never in a legal document
Edinburgh Agreement 15 Oct 2012 signed by David Cameron, Alex Salmond, Michael Moore and Nicola Sturgeon only says they will "deliver a fair test and a decisive expression of the views of people in Scotland and a result that everyone will respect". It does not contain "once in a generation" or "once in a lifetime".
The phrase came from campaign rhetoric to maximise turnout. The White Paper Scotland's Future called it a "once in a generation opportunity", and on Andrew Marr 2014 Salmond described it as a once-in-a-generation opportunity.
Salmond later said on BBC 5 Live:
"The phrase was not once in a lifetime, it was the opportunity of a lifetime."
His point was it was a political rally call at the time, not a legal clause that would bar future referendums. Westminster later treated it as a pledge.
enough to make that case and allow people to decide."enough to make that case and allow people to decide."It was never in a legal document.