ONE of the UK's most senior politicians attempted to block his son's dream of becoming a Tory MSP but was talked out of it by the leader of the Scottish Conservatives.

Ruth Davidson revealed that she had personally intervened in the family row after Oliver Mundell, son of Scottish Secretary David Mundell, complained to her that his dad was "blocking him" from standing for Holyrood next May.

The 26-year-old asked Ms Davidson to "have a word" with his father, leading to what she described as "the worst phone call ever" when she gently reminded the Secretary of State that his newly-married son was "a grown man".

Oliver, who has a first-class degree in constitutional law and legal theory, passed the internal selection process, which operated independently of the party's leadership, and will stand as the Conservative candidate in the Dumfriesshire constituency where he faces a three-way fight with Labour and the SNP.

He will also be a regional list candidate, with the rankings to be announced at the weekend following what Ms Davidson described as the "biggest exercise in grassroots democracy this party has ever undertaken". She pledged that a new-look party would look and sound like modern Scotland, with a series of long-serving party MSPs preparing to step down.

Speaking to journalists after a speech in Edinburgh where she fired the starting gun on the election campaign 150 days out from the vote, she said: "I had a very interesting conversation with David Mundell's son, Oliver, who came up to me and said that his dad was suggesting that he couldn't stand.

"He asked me if I could have a word with dad because he'd passed everything... So I had to have the worst phone call ever, of phoning David and going 'I know that you don't want a politician's life for your son, I know why given the difficulties that you've had, I know how tough it is. But he's done this, he should be treated the same as everybody else, because until then he has been treated the same as everybody else. So I have to ask you to let him do this, and make his own mistakes because he's a grown man'."

She added: "So that was a very difficult conversation but we've now started a political dynasty because he got selected to fight the Dumfriesshire seat and will be ranked [on the regional list] this weekend. I'm out on the campaign trail with him on Saturday at a coffee morning in Moffat."

In her speech, Ms Davidson also made an overt pitch to Labour and Liberal Democrat supporters who oppose Scottish independence, saying the parties had adopted a "pathetic and weak" approach to the union.

She insisted she was "no ideologue" when it came to policy, as she took on both the left and the right in a pitch to centrist voters. She said: "Some on the right say 'hand more power to the market', when we all know that the market has too often been shown to be rigged against working people. The left says 'hand more power to the state', when we all know the state has failed and is failing to respond to our personal needs.

"My plan for this election is to use our strong foundations within the United Kingdom to set out a new vision. Not bowing to the big state on the one hand or genuflecting to the free market on the other - but of an active and energetic government which seeks to create a more level playing field for all.

"A moderate government which knows that the state can't do it all and shouldn't try to - but knows that the state can strengthen society when used well."