So, what are we to make of Mhairi Black, the youngest person to be elected to parliament in modern times? This week, the SNP MP for Paisley and South Renfrewshire gave her maiden speech, and quite a lot of people made quite a lot of her, most of them – but by no means all – on social media. It was easy to see why.

As a rhetorician, Black was perfect. Disregarding, for a moment, the content of her speech, it’s surely impossible to dispute that Black’s presentation was absolutely right. She was far from overwhelmed by the occasion, but there was no hint of arrogance. A couple of minor failures of cadence – early on, and almost immediately recovered from – served only to remind the listener that all this was new to Black, and that she was good at it because it came naturally. Her authenticity, her commitment to her cause, was totally, almost casually, apparent. Plus – jokes.

Labour must get over its hurt and start working with the SNP | Mhairi Black Read more

Black’s position, as the baby of the House of Commons, embodies the sense of hope that her party ignited in Scotland during the referendum campaign. She’s living proof that when the yes campaign persuaded young people that political engagement was worthwhile, they weren’t merely selling a dream. Black’s potential was spotted with alacrity, and seized upon without hesitation. It’s hard to argue that her party’s belief in her was frivolous or misplaced.

On the contrary, their championship of youthful ambition speaks of a willingness to spot and promote talented people, rather than people who feel their turn has come. This sense of an urgent need to develop fresh voices has been lacking in the Labour party for a long time now, and has been particularly obvious north of the border.

Black’s speech certainly pointed up the advantages that youth – especially when it’s connected to grassroots activism – can lend to a politician. The electorate is wary of politicians from the “I met a man who ...” school. The impression is often of a professional voteseeker who has been carefully introduced to a member of the public precisely so that their story can be aired as part of a party-political narrative. Black is encumbered by no such constraints.

In her maiden speech, Black spoke of meeting a man who had fainted from hunger on his way to the jobcentre and been sanctioned for 13 weeks because this had made him 15 minutes late. In her first speech to the SNP conference last year, she spoke of meeting a woman who, when she and her two-year-old approached Black as she campaigned in the referendum, was looking for food, not debate. The poorest areas, Black pointed out, voted most enthusiastically for yes.

But it’s not only Black’s own passionate idealism that allows her to deliver such stories without seeming exploitative. She also benefits from the youth of her party as a major and influential player. The SNP, limited in its power to drive change in Holyrood and new to significant success in Westminster, is not greatly limited by past choices and past failures. Plenty of people in the Labour party want to expose the sort of misery that Black is exposing, and are frustrated that their party’s leadership is too busy, as Black said in her speech, “desperately trying to vacate the left to own the centre”.

In truth, however, Labour’s problem is that it has to come up with something the SNP, as yet, doesn’t have to come up with – a workable alternative to tax and spend. So many people in Labour feel the same way as Black that one poll is suggesting leftwinger Jeremy Corbyn will win the Labour leadership contest.

This would solve one Labour problem that Black exposed, Corbyn being a dab hand at stirring socialist rhetoric himself. But that’s the easy problem to solve. The hard problem, as Greece knows, isn’t promising to end austerity – it’s coming up with a credible plan to do so. If the SNP has one, and if it really wants to create an effective opposition in tandem with Labour, then it really ought to start spilling the beans on precisely what the plan is.

I don’t doubt Black’s sincerity in extending the hand of friendship to Labour. I share her disgust at Harriet Harman’s airy announcement that Labour will back the Tories’ benefit changes. But I also find it irritating that Black’s sincerity seems to include a sincere failure to understand that the SNP is not Labour’s most natural ally in Westminster, but Labour’s most insidious opponent. The vast majority of the UK electorate doesn’t want a Labour-SNP alliance to be the chimerical alternative to the Conservatives in Britain. And the vast majority of the UK electorate can only reject Labour to stop that from happening.

I’m glad Scotland has found a way to refresh and reinvigorate its politics. I hope the rest of the UK finds one, too. But the rise of the SNP is a consequence of Labour’s decline; the SNP is not a helpful friend at a difficult time. I think Mhairi Black is wonderful. But you don’t join a nationalist party because you want to help the union that your party exists to dismantle.

Rhetoric is a fine thing. But it doesn’t feed hungry old men or hungry young children. Black’s constituency is lucky to have her. So is her party. But while she has every right to abhor Labour’s love of the centre ground, she and her party are helping to push Labour in that direction, even as they insist they are not. There is no political need for her and her colleagues to stop doing so, because the SNP can only gain from it. The sad thing about Black’s speech, among many happy things, is that it shows you can be passionate, sincere and inspiring, but also utterly mistaken.