There’s something strange going in within the Liberal Democrats, and it isn’t helping us, or showing us up in a very favourable light.

Last month we had an astonishing success in the Richmond upon Thames borough elections. In 2014 the Conservatives won 39 of the 54 seats; this time we won 39, reducing the Tories to 11 and the Greens picked up four thanks in large part to an arrangement with us. It was an outstanding achievement for Gareth Roberts and his team.

But in the weeks since then, there seems to be a movement afoot trying to pretend that cooperating with the Greens wasn’t such a good idea after all, and that if we’d only stood a full slate of candidates in the four wards where the Greens got councillors elected, we’d have had 43 seats and the Greens none. This is the broad thrust of an article by Theo Butt Philip in ‘Liberator’, of a verbal analysis given by Richard Cole of the ALDC to the South East Region, and of several comments I’ve seen in response to blogs.

I find this line of argumentation both counterproductive and rather sad. For a start it seems to begrudge the Greens four seats, which they will use to keep us honest on environmental lines. If I’m in a room and there are Green or Green-leaning people there, it soon becomes clear there’s far more that unites than divides us, so why should we be mean-spirited when it comes to working with them to our mutual benefit?

Aside from any moral considerations, the argumentation is of poor quality. Who says we would have won the four seats the Greens won if we’d fielded three candidates in those wards? The chances are the Greens would have still fielded their candidate, we’d have split the ‘progressive’ vote, and the Tories might have picked up another member.

I canvassed in two of the split wards in Richmond, and it was clear the LibDem/Green deal was popular on the doorstep. I can’t judge exactly how popular, but a lot of people welcomed the idea of two parties cooperating rather than dissing each other. In one ward both we and the Greens felt a long-serving Conservative councillor was bound to get in by dint of his personal vote, but he was ousted by the cooperating parties – you’d have to make a very strong case that we’d have won all three seats in that ward.

The most egregious part of the argument that we lost more than we gained is the failure to consider the parliamentary element. The LibDem/Green arrangement in Richmond was never solely about the council – it was a deal around two parliamentary constituencies and the council. The Greens stood aside in the Richmond Park by-election in 2016 and the Richmond Park and Twickenham seats in the 2017 general election to enhance our chances of winning, and indeed we won two of those three elections. As payback, we agreed to stand aside one candidate in six wards to help the Greens in the council elections.

It’s still possible to argue Richmond was not good for us, but to do so one would have to compare what we gained in the three parliamentary elections with what we lost to the Greens in the council elections. Failure to do this makes any analysis limited and misleading. Dare I say it would be a bit like someone saying ‘Grammar schools are wonderful, look at their results!’ without considering the overall impact of grammar schools on secondary education – we come down on this argument like a tonne of bricks, yet we condemn the Richmond initiative using painfully selective evidence.

And ultimately, how are we ever going to get fair votes if we don’t work with other parties of broadly similar mindset who are as committed to PR as we are? The Greens have been willing to work with us because they know PR will help them, so why doesn’t the logic work the other way round? Fighting the Greens in a way that lets Conservatives win is daft, yet I fear this tribal thinking will scupper some potential arrangements with the Greens for the May 2019 local elections which, if linked to smart campaigning at the next general election, could enhance the chances of getting PR.

Let’s be clear: there are situations where cross-party cooperation doesn’t make sense, and, even where it does, standing candidates aside isn’t always the best option. It’s a subject on which we Lib Dems need to have a healthy and open-minded discussion. But resorting to such poor-quality arguments is counterproductive, and it also leads to the suspicion that we are not as liberal as we like to think we are and succumb frighteningly easily to the temptation to take refuge in tribalism.

* Chris Bowers was a two-term councillor on Lewes District Council and a co-editor of "The Alternative" which explored the idea of a progressive alliance.