Her address to the Scottish Parliament on Scotland's political future will also cover the fallout from the Brexit turmoil at Westminster following the extension agreed until the end of October.

The SNP leader has been pledging to make a statement on her plans for a second independence referendum for months, but insisted she needed more clarity on Brexit before she could set out her thinking.

Scottish independence: First Minister held to ‘Sturgeon Test’ of indyref2 suppo...

Nicola Sturgeon will update MSPs on Wednesday

A meeting of Holyrood's parliamentary bureau on Tuesday will consider the change to scheduled business tomorrow afternoon, but this is expected to be a formality.

Leading figures in the independence movement, such as Greens co-leader Patrick Harvie, have been stepping up the pressure on Ms Sturgeon to forge ahead on the referendum issue, but the First Minister has urged caution as polls show no movement towards Yes.

The Tories have pointed to the SNP’s Holyrood manifesto launch in April 2016 when Sturgeon said that she would not bring forward a referendum before a majority of Scots wanted it. Polls indicate there is still no majority support for a Yes vote.

Indyref2: Sturgeon to update MSPs on referendum plans