Video report by ITV News Correspondent Neil Connery

Scottish Conservative leader Ruth Davidson has revealed the extent of her struggle with mental health and self-harm.

In an interview with The Sunday Times, Ms Davidson, who is pregnant with her first child, told how she was diagnosed with clinical depression at 18 and battled suicidal thoughts.

Ms Davidson's personal popularity and electoral success has seen her frequently tipped as a future leader of the UK party.

But the 39-year-old admitted that for the sake of her mental well-being and relationship she would never take on the job as prime minister.

Ms Davidson ruled out such a move and dismissed claims she could take a peerage or move south and become an MP as "bollocks".

She told the newspaper: "No. I value my relationship and my mental health too much for it. I will not be a candidate."

Ms Davidson and her partner Jen Wilson are expecting a child. Credit: PA

She added: "On a human level, the idea that I would have a child in Edinburgh and then immediately go down to London four days a week and leave it up here is offensive, actually offensive to me."

In extracts from Ms Davidson’s memoirs, printed by the newspaper, she tells how the suicide of a boy from her home village when she was 17 sent her into a "tailspin".

A year later she was diagnosed with clinical depression but the medication gave her "desperate, dark, terrible dreams".

"I started having suicidal thoughts," she wrote.

Ms Davidson said she is "still frightened" of going back to the "psychological place I once inhabited".

She said she turns to "structure, exercise, forward momentum, measurable outcomes" when she is feeling anxious.