Nicola Sturgeon has signed a letter asking the UK Government for a second referendum on Scottish independence.
The Scottish Government tweeted a picture of the First Minister with her feet up on a couch in her Bute House residence writing the Section 30 letter on Thursday evening.
This week, MSPs voted by 69 to 59 in favour of seeking permission for an independence referendum to take place between autumn 2018 and spring 2019.
Ms Sturgeon said her mandate for another vote is now "beyond question", and warned it would be "democratically indefensible and utterly unsustainable" to attempt to stand in the way.
Scottish Secretary David Mundell said the UK Government would decline the request.
Ms Sturgeon is pressing ahead with a formal approach for a section 30 order - the mechanism for the powers to hold a referendum.
The Scottish Government tweet read: "First Minister @NicolaSturgeon in Bute House, Edinburgh, working on final draft of Section 30 letter to Prime Minister Theresa May."
It is expected to be sent to Downing Street on Friday.