Sturgeon aims for Scottish independence referendum by 2021

Speaking at the Scottish Parliament, Sturgeon said a second independence referendum should be held "in the lifetime of this parliament" adding that the Scottish government will aim to pass framework legislation for such a public vote before the end of 2019.

"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," said the Scottish National Party Leader.

Any referendum would require Westminster's consent in order to be viewed as fully legal and it seems unlikely that Theresa May would allow for any vote to proceed, with a spokesman for Number 10 stating that her opposition to a second independence vote "has not changed".

Scotland last had an independence referendum in 2014, when a 55% majority voted to remain in the UK.

The Westminster government's Scottish Secretary, David Mundell said: "Instead of respecting that result, Nicola Sturgeon continues to press for divisive constitutional change when it is clear that most people in Scotland do not want another independence referendum. The UK government will stand up for them."

However, supporters of a second referendum argue that Britain's planned exit from the European Union has changed the landscape, with Scottish voters having overwhelmingly supported the 'remain' bid.