Ruth's home truths: Tory Queen of Scots hammers her own party on tax credits, attacks Jamie Oliver's sugar tax and asks 'Why can't a Scot be PM anymore?'

George Osborne last night suffered a new blow on the eve of a House of Lords bid to stop his tax credits cuts when the Tory Party’s leader in Scotland, Ruth Davidson, backed the growing Conservative revolt.

Rising star Ms Davidson said it was wrong for low-paid workers to lose out.

Using emotive language that piles pressure on the Chancellor, she said no one should ‘fall off a cliff’ when the tax credits are axed in April. Critics claim some people may initially lose £20 a week.

Scottish Tory leader Ruth Davidson who has slammed Chancellor George Osborne over his plans to cut tax credits

During a wide-ranging and at times uproarious interview with The Mail on Sunday, Ms Davidson:

• Fuelled claims that she could pursue her ambitions in Westminster, saying it is ‘utter rubbish’ to say a Scot can no longer be Prime Minister.
• Lambasted 'rocket-munching millionaire' Jamie Oliver over the 'sugar tax'. 
• Mocked the referee blamed for Scotland's rugby World Cup exit; and...
• Talked of her relationship with Jen Wilson, saying she feared it may be too late to achieve her dream of having children. 

We chatted the morning after her debut on the BBC’s Have I Got News For You satirical quiz show.

‘I was expecting to get pelters, but didn’t,’ she says. For a Sassenach, it helps to have a Glaswegian slang dictionary when interviewing her. I didn’t. ‘Pelters’ apparently means to be roundly abused.

Davidson, 36, a former Territorial Army reservist who kick-boxes in her spare time, is a pugnacious ball of energy.

On Have I Got News, Ian Hislop and co teased her over her increasingly frantic tweets during the Australia versus Scotland rugby match when the Scots lost owing to a blunder by the referee, who ran off at the end.

Seizing on her well-known love of cocktails, the HIGNFY team suggested the tweets were fuelled by more than patriotism.

Davidson spent most of the day of the match drinking vodka and Cokes in Edinburgh’s trendy The Place bar, followed by ‘a couple of French martinis’ afterwards.

Miss Davidson practising her kick-boxing. She has been tipped as a future UK Conservative leader by David Cameron himself

Was she drunk? ‘Pleasantly merry,’ grins the pocket Dawn French of Scottish politics.

She hoots with derision at a claim that the ref fled the pitch because he needed the lavatory. ‘If 40,000 Scots were screaming at me, I’d have been crapping myself too!’

Davidson’s self-confessed Twitter obsession has come at a price: she has been targeted by internet trolls. ‘I ignore the “ugly fat useless stupid bastard” comments,’ she says. 

But not jibes about her sexual orientation. ‘Half of all young gay people have been homophobically bullied; when they see public figures like me saying it’s not on, they know they don’t have to take it either.’

She is not cowed by the formidable SNP leader Nicola Sturgeon, and even less so by her own boss, David Cameron, raging at his ‘bloodless and gutless language’ in the Election, claiming the Tories must show more compassion and passion, not a quality lacking in her as she throws down the gauntlet over tax credits.

‘If we’re not the party of getting people into work and making it easier for them to get up the tree, then what are we there for? It’s not acceptable. The aim is sound, but we can’t have people suffering on the way. The idea that there’s a cliff edge in April before the uptake in wages comes in is a real practical human problem and the Government needs to look again at it.’

Miss Davidson says he is not cowed by the formidable SNP leader Nicola Sturgeon, and even less so by her own boss, David Cameron

Davidson has been tipped as a future UK Conservative leader by Cameron himself. Certainly, her prospects in Scotland, rapidly turning into a one-party state led by the SNP’s ‘Queen’ Nicola, with Ruth as out-of- favour ‘Princess’ of the ‘toxic Tories’, don’t look great.

She admits admiring Sturgeon personally ‘while disagreeing with everything she stands for’.

Will self-styled ‘blue-collar Tories’ champion, devout Christian and radical lesbian Davidson move South and seek a political pulpit for her bustling talent in Westminster, as many believe?

‘Erm, at the moment I’m not looking past the big job I have to do in Scotland. I’d never rule it out but it’s not at the top of my to-do list.’

If politicians’ denials were marked out of ten, with ten for a genuine denial, I would score Davidson’s at four. ‘I’ve seen behind the curtain at No. 10 and don’t really fancy it,’ she claims. But it only needs a gentle prod about it being time for a change from Tory posh boys for her working-class Glaswegian roots – and political ambition – to burst through as spikily as her tomboy fringe.

Name-checking fellow Tory Cabinet Ministers with humble origins, she delivers a rally cry: ‘There’s a strong blue-collar streak in the Conservative Party, whether it’s Patrick McLoughlin [a former miner], Stephen Crabb [son of a single mother], me, Justine Greening [educated at a Rotherham comprehensive school] or Sajid Javid [a Pakistani bus driver’s son].’

‘If and when the current Prime Minister steps aside, you will hear voices from that wing of the party speaking pretty loudly in the leadership election.’ Note the oh so casual reference to ‘the current Prime Minister’. Likewise, she scoffs at the notion that, with a breakaway Scotland seemingly only a matter of time, a Scot can never be UK Prime Minister again. ‘Utter nonsense. Of course they can.’

As we chatted at the coffee bar at London’s City Airport while Davidson waited for her flight home on Friday, she ignored fresh croissants and sipped on a Diet Coke.

Did she support Jamie Oliver’s call for a sugar tax to tackle obesity? ‘I was watching Jamie Oliver and thinking, “You rocket-munching millionaire, telling people they’re not allowed a bloody Curly Wurly!”

‘The libertarian in me was like, “Actually, sod off, just sod off. If folk want a Twirl, let them have a Twirl!”

‘I’m all for informed choices, but bloody hell, nanny state!’ she fulminates. ‘You don’t have VAT on bread, meat, fish or fruit but you do on cakes, sweeties, sports drinks and the rest. And guess what? It’s set at 20 per cent – which is what they want for the sugar tax. We already have one!’

She used an Election broadcast to tackle stereotypical attitudes to gays, appearing with her partner, charity worker Ms Wilson, 33. However, contrary to recent reports, it appears the couple are not about to start a family.

‘Since I was about 25 I’ve always thought that I’d quite like children in about five years. But I’m now 36, so I don’t have a lot of five years left. And I’m not exactly in a position where it can happen by accident, shall we say?’

It seems an appropriate moment to draw the interview to a gentle close. But Ruth has other ideas. ‘You didn’t ask me my weight!’ she chuckles, a reference to the public mauling I received when I put the question to Labour MP and keep-fit fanatic Liz Kendal who – rightly – gave me a blunt, two-word reply.

OK, so how would perky pitbull Ruth have responded, I ask, walking into her trap. ‘Just the same, “Get tae f***, big man!” ’ I don’t need a Glaswegian dictionary for that.