In a statement to MSPs at Holyrood on Wednesday, the First Minsiter said: "A choice between Brexit and a future for Scotland as an independent European nation should be offered in the lifetime of this Parliament.
"I can confirm that the Scottish Government will act to ensure that the option of giving people a choice on independence later in this term of Parliament is progressed."
She said Westminster has failed to protect Scotland's interests and that the Scottish Government is taking steps to rectify that by introducing legislation to set out rules for another vote.
The First Minister said: "Throughout this, the Scottish Government have worked tirelessly to help find the best way forward for all of the UK.
"Whatever Scotland's constitutional status in the future, it will always be in our interests for these islands to have the closest possible relationship with the EU.
"We have done everything possible to help avert the Brexit crisis for the whole UK. And we will continue to do so."
A Number 10 spokesman said on Tuesday that Theresa May's stance on the issue of a second Scottish referendum "has not changed" - with the PM having previously made clear her opposition to such a ballot.
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