Roughly a year ago I write an article in the Guardian criticising Jeremy Corbyn and his leadership of the Labour Party.

I was deeply disappointed by his team's Brexit campaign.

What I had seen was, I thought, shambolic from press relations onwards.

Policy was not forthcoming.

I had lost confidence. I was far from alone.

What I could not have anticipated was a speech as good as this:

Jeremy Corbyn has grown into the role of Labour leader in ways I could not have anticipated. I owe him an apology. It turns out I was wrong. He can do the job. That's why I signed a letter to the Observer yesterday.

I make it clear that this does not mean I think Labour have everything right. The manifesto has weaknesses. The tax policy is not all I would want, for a start. The economic policy still pays too much regard to neoliberal thinking. But it's better than the anything the Tories are offering. And it's ample enough to persuade me that voting Labour will be the right thing to do in many cases.

That said, if a vote for another party would help stop a Tory get elected and so prevent the harm to the well being of so many people in this country I would vote tactically, even if I am not greatly persuaded by the LibDems. If, however, a Green candidate had a hope I would vote for them. My attitude north of the birder is well known. I understand why people vote SNP.

By saying so I make clear my politics is not tribal and I wish Labour's was not. That, in my opinion, is its greatest weakness.

But let me be clear: it has a plausible leader. I did not expect Jeremy to become that. I was wrong. And I apologise. I underestimated him.