Labour has just kicked off its first big wave of expulsions, purging many voters from the party’s leadership rolls. Twitter is ablaze with activists who believe they have been kicked out because they are supporters of Jeremy Corbyn. There are, I'm told, more expulsions to come - what's going on? Is Labour purging its rolls of Corbyn supporters?

The short answer is “No”.

If that opener feels familiar, it should: I wrote it last year, when the last set of purges kicked off, and may end up using it again next year. Labour has stringent rules about expressing support for other candidates and membership of other parties, which account for the bulk of the expulsions. It also has a code of conduct on abusive language which is also thinning the rolls, with supporters of both candidates being kicked off.

Although the party is in significantly better financial shape than last year, it still is running a skeleton staff and is recovering from an expensive contest (in this case, to keep Britain in the European Union). The compliance unit itself remains small, so once again people from across the party staff have been dragooned in.

The process this year is pretty much the same: Labour party headquarters doesn’t have any bespoke software to match its voters against a long list of candidates in local elections, compiled last year and added to the list of candidates that stood against Labour in the 2016 local and devolved elections, plus a large backlog of complaints from activists.

It’s that backlog that is behind many of the highest-profile and most controversial examples. Last year, in one complaint that was not upheld, a local member was reported to the Compliance Unit for their failure to attend their local party’s annual barbecue. The mood in Labour, in the country and at Westminster, is significantly more bitter this summer than last and the complaints more personal. Ronnie Draper, the general secretary of the Bfawu, the bakers’ union, one of Corbyn’s biggest supporters in the trade union movement, has been expelled, reported for tweets which included the use of the word “traitors” to refer to Labour opponents of Corbyn. Jon Will Chambers, former bag carrier to Stella Creasy, and a vocal Corbyn critic on Twitter, has been kicked out for using a “Theresa May” twibbon to indicate his preference for May over Andrea Leadsom, in contravention of the party’s rules.

Both activities breach the letter of the party’s rules although you can (and people will) make good arguments against empowering other people to comb through the social media profiles of their opponents for reasons to dob them in. (In both cases, I wouldn’t be shocked if both complaints were struck down on appeal)

Further fueling people's anger is that David Sainsbury, a Labour peer, has not had his vote rescinded despite having donated £2m to the Liberal Democrats, as the sum was ringfenced for the referendum campaign, a contest in which the two parties were officially co-combatants. (This allowed Sainsbury to get around regulations about the size of donations in the referendum by "triple-dipping". Similar mechanisms were used by Brexit's biggest donors. The whole thing raises questions about the efficiency of British campaign finance laws, but not Labour's vetting process.)

I would be frankly astonished if Corbyn’s margin of victory – or defeat, as unlikely as that remains in my view – isn’t significantly bigger than the number of people who are barred from voting, which will include supporters of both candidates, as well as a number of duplicates (some people who paid £25 were in fact members before the freeze date, others are affliated trade unionists, and so on).

What is unarguably more significant, as one party staffer reflected is, “the complaints are nastier now [than last year]”. More and more of the messages to compliance are firmly in what you might call “the barbecue category” – they are obviously groundless and based on personal animosity. That doesn’t feel like the basis of a party that is ready to unite at any level. Publicly and privately, most people are still talking down the chances of a split. It may prove impossible to avoid.