Boris Johnson has ruled out granting permission for a second vote on Scottish independence while he is prime minister.

Mr Johnson said his government would not give the go-ahead for another legally-binding referendum.

The Tory leader claimed the issue had been settled in a "once-in-a-generation" vote in 2014.

Nicola Sturgeon described the position of blocking another independence referendum as "unsustainable".

The Scottish first minister has already said she will request a "section 30 order" - which grants permission for a new referendum from the UK government - within days of the 12 December general election.