Scottish Conservative leader Ruth Davidson is backing Jeremy Hunt as he bids to defeat Boris Johnson and become the next prime minister.

Hunt is the third candidate Davidson has supported in the Conservative leadership race, after her first two preferred choices - Sajid Javid and Michael Gove - were knocked out of contention.

Announcing her endorsement on Twitter, the Scottish Tory leader praised the foreign secretary for putting "the union first".

Davidson threw her weight behind Javid, the home secretary, early in the contest, until he was eliminated  in the fourth ballot of Tory MPs last week.

She then switched her support to Gove, but in the final MPs' ballot later that day the environment secretary was pipped by Hunt.

She tweeted: "Any Conservative leadership candidate must put the union first.

"Jeremy has done so and will get my vote."

Her backing for the foreign secretary comes the day after her party deputy, Jackson Carlaw, endorsed Hunt and slammed Johnson during a live Scotland Tonight debate on STV.

It also follows a weekend visit to Scotland by Hunt, where he claimed he would "never allow the union to be broken up as prime minister".

Johnson's campaign has its own Scottish backers, with north-east MPs Ross Thomson, Douglas Ross and Colin Clark claiming at the weekend the former London mayor would "swat" the SNP "like midges".

Thomson, MP for Aberdeen South, was also appointed by Johnson to manage his campaign north of the border.