The ‘Red Tory’ name-calling - which I thought my party had knocked on the head since the summer, yet was rekindled yesterday - has got to stop.

It is one thing to describe somebody as ‘foolish’. We can all be foolish. It’s natural to think other people ‘wrong’ or ‘naïve’. I would go so far as to say even ‘pathetic’ or ‘stupid’ maybe unnecessary, but it's not that hurtful. But telling a fellow Labour member that they are a conservative is something different.

John McDonnell stepped over that line on Wednesday when he said Progress, the group of Labour activists I chair, pursues a ‘right-wing conservative agenda’ and are somehow ‘hard right’. First I gave him the benefit of the doubt - we all misspeak when we are tired- but he went on to repeat this disappointing slur as he toured the media studios in an attempt to defend the messy and divisive reshuffle he has been helping to organise. He clearly meant it and, as Shadow Chancellor, he should know better.

So what is in this conservative philosophy that I it to be a term of abuse? Conservatives value the status quo and have a poverty of ambition for those with less in society that I reject utterly.

For some in politics, the answer to a rapidly changing and turbulent world is to lament the passing of years gone by, and to try to apply a break to progress. They are conservative because they want the conservation of the past as a political end in itself. Tories are not progressive. They are conservative.

Whether it’s George Osborne’s defence of damaging culture in banking, or the cuts to tax credits that will hammer lone parents, this is conservatism in action. Standing up for the old order: the few rather than the many.

And the reason why I could never be a conservative is that much about our past in fact was really, really bad for people: oppression of working classes, women, how those with disabilities were treated, racism, xenophobia and discrimination towards the LGBT community.

So when it comes to the conservative establishment, Labour is, naturally, the rebel party, and I’m proud of that.

Labour - and Progress for that matter - are the radicals of British politics. We have a big vision for our country and are ambitious for all our citizens. Some may say we are on the back foot politically, and for sure, we must accept the result of the Labour leadership election in September. But when it comes to politics, I never give up.

This September at Labour conference, I listened to young members tell me about their experiences growing up under Labour. Change has happened. Not for them that sinking feeling that those in power just didn't really care. Rather, they told me how the EMA and the re-introduction of a maintenance grant for those who really needed it had made them feel that the Government was behind them, investing in them.

That’s the difference when a political movement has power. Giving the people we serve a voice, a proper chance, and a decent government that works every day to help, come what may. That is what it means to be a progressive: to demand and achieve change.

If there is a difference between various members of the Labour movement, as I’ve said before, I suspect it is between those of us who are desperate to change our country and see progress happen, and those who find the politics of protest a better virtue signal. They are wrong not to be serious about real power.

But allow me to end on a note of harmony.