A letter from the First Minister formally requesting the powers to hold a second Scottish independence referendum has been delivered to Downing Street.

The request penned by Nicola Sturgeon was sent to Prime Minister Theresa May on Friday morning.

MSPs voted by 69 to 59 this week in favour of seeking permission for an independence referendum between autumn 2018 and spring 2019.

In her letter, Sturgeon said: "In these very changed circumstances, the people of Scotland must have the right to choose our own future - in short, to exercise our right of self-determination."

The UK Government has said it will decline the request, with May repeatedly stating "now is not the time" for another vote on the issue.

However, Sturgeon has said her mandate is "beyond question" and is pressing ahead with a formal approach for a Section 30 order - needed to transfer the powers to hold a referendum.

In the letter, Sturgeon said there appears to be "no rational reason" for the UK Government to "stand in the way of the will of the Scottish Parliament", adding: "I hope you will not do so."

A UK Government spokeswoman said: "The Prime Minister has been clear that now is not the time for a second independence referendum, and we will not be entering into negotiations on the Scottish Government's proposal.

"At this point, all our focus should be on our negotiations with the European Union, making sure we get the right deal for the whole of the UK.

"It would be unfair to the people of Scotland to ask them to make a crucial decision without the necessary information about our future relationship with Europe, or what an independent Scotland would look like.

"We have been joined together as one country for more than 300 years. We've worked together, we've prospered together, we've fought wars together, and we have a bright future. At this crucial time we should be working together, not pulling apart."

STV News requested to interview Sturgeon on Friday in relation to the letter.

However, this was declined by the Scottish Government, which stated we could use an interview given to BBC Scotland that was to be made available to other broadcasters.

An STV spokesman said: "STV regrets that, on such a significant news event, the Scottish Government would not make the First Minister available for interview by STV News. That decision puts our viewers at a significant disadvantage, as we are not able to scrutinise the issue in a way that is consistent with our editorial standards and our requirements for thorough reporting."

During the interview with BBC Scotland, the First Minister refused to outline her plan should May reject her latest pleas, as expected.

Sturgeon said: "Now, if she refuses to enter into those sensible discussions, as I anticipate in the letter that she might, what I've said very clearly is this - in my view, the Scottish Parliament should be respected.

"It's not a question of if it should be respected, but how. If she chooses not to do that, then I will set out to parliament over the next few weeks, what I intend to do to make sure that the will of the parliament is respected and we make progress towards giving the people of Scotland the choice."

She added: "I will go into that in due course. Today, I'm setting out the will of the Scottish Parliament expressed on Tuesday of this week. I've heard and considered carefully the Prime Minister's public position and I set out some of my response to that in the letter.

"I would anticipate that the Prime Minister would stick to that position. I have a clear idea in my mind as to what I would do as a result of that, but I will set that out in due course to parliament in the fullness of time."