Jackson Carlaw stepped down as leader of the Scottish Conservatives on Thursday, saying he is not “the person best placed” to put forward the argument Scotland remaining in the UK.
“Nothing is more important to me than making the case for Scotland’s place in the United Kingdom", he said in a statement.
“I believe the Scottish Conservative and Unionist Party is the most important voice in Scotland for setting out that positive argument. I am clear that nothing must get in the way of doing so".
He said that due to the "importance" of the job he has "decided to stand down with immediate effect". The decision was not "easy", he said, but "party and country" must come first.
Carlaw's resignation comes less than a year after he was elected to the position in February following a period as interim leader after his predecessor Ruth Davidson stepped down due to maternity leave with the Westminster leadership.
Prime Minister Boris Johnson gave tribute to the outgoing leader saying that he has "been a tremendous servant to the Scottish Conservative Party for more than four decades".
“As an activist, deputy chairman, deputy leader and leader, he has given his all and deserves our thanks for his efforts.
“It is a mark of his commitment to the cause that he chooses to stand aside at this time and I offer my best wishes to him, Wynne and the family.”
His exit comes just under a year before the next Scottish Parliament election, which is scheduled for May 2021.
Opinion polls show the ruling Scottish National Party holding a comfortable lead ahead of the Conservatives and Labour. Other polls show that sentiment in support of independence has risen in correlation with Carlaw's ascension to the leadership position.
The 61-year-old has sat in Holyrood since 2007, beginning on the regional list for the West of Scotland before a victory in Eastwood constituency in 2016.