Labour have been fighting off claims that they are losing huge numbers of members.

Newspaper reports claimed this week that the party had lost 100,000 members or more over the last year.

If true, this would be damaging for Labour, who emphasise grassroots support for the party under Jeremy Corbyn’s leadership.

Labour have publicly called the story a “total fabrication” and “completely made up”. But they have declined our requests to provide any figures that prove it wrong.

The last time Labour published official membership figures (for December 2017) they said they had a massive 564,000 members. But is this number trustworthy?

FactCheck understands – based on the party’s own rulebook, leaked internal documents, and sources with detailed knowledge of Labour processes – that the way Labour calculate their membership figures allows them to include people who haven’t paid their fees for up to 18 months in the official tally. The Labour party deny this.

In arrears

Political parties are not legally obliged to publish information on their membership figures. Most are less than transparent on the matter – as FactCheck found in October when the Conservatives were unable to provide stats to back up their claims about a purported rise in young recruits.

Labour voluntarily include “the total individual membership of the Party” in their annual accounts, which they submit to the Electoral Commission each year.

The latest accounts, published in August 2018, state that “as at 31 December 2017 the total individual membership of the Party was 564,443”.

Labour told us that this number includes individuals who are in arrears – behind with payments on their party membership fees.

How long can you be in arrears before you are no longer considered a member?

When you join Labour, you can pay a whole year’s subscription fee in one go with a single annual payment.

But Labour tell us that the “vast majority” of members pay in monthly instalments through Direct Debit.

Even if you opt to pay monthly, the rules say you begin a membership year defined as “12 months from the date of joining the Party”.

The rule book goes on: “All members shall be issued with a card… which shall indicate the expiry of their membership year…

“An individual member shall be deemed to be in arrears from the expiry date until they renew their subscription.

“An individual member shall be deemed to have lapsed from membership if s/he has been in arrears for six months and has not paid following a request to pay the arrears.”

That looks like you could stop making monthly payments after the first one, and Labour would not start chasing you until the end of a full year of membership. And that then, they would give you another six months to pay up before striking you off the list of members.

So if you tried to leave Labour one month into your “membership year” by cancelling your monthly Direct Debits, could you still be considered a member for up to 18 months? Sources with detailed knowledge of Labour party processes told FactCheck that this was indeed the case.

And it appears to be the understanding among party officials. A leaked “weekly internal update” from January 2018 quoted a Labour staffer: “The number of lapsers in the period is high as a result of a spike in joiners around 18 months ago.” The suggestion here is that the party assumes that it takes a year-and-a-half for some members to come off the books after they stop paying.

How many people are allowing their membership fees to lapse because they disagree with the direction the party is taking? How many are stopping payments because they can’t afford them? It’s hard to say.

But those who thought they’d left the party by stopping their Direct Debits may be surprised to learn that they could have stayed on Labour’s books long after that.

What do Labour say?

We put all this to Labour.

They told us “this is nonsense. No one has been a member for eighteen months without paying. The Party allows members a six-month window to update their payment information and pay off their arrears before their membership lapses, as do many membership organisations.

“When membership lapses after six months, they cease to be members. This isn’t new information.”

The party accepts that people who are behind on their payments are included in their official membership count – they’ve never denied this, although it’s not spelled out in the accounts they submit to the Electoral Commission.

The sources FactCheck spoke to are clear that the “six-month window” where someone is officially in arrears only begins after the membership year expires – something that is also suggested by the party rulebook.

It’s hard to escape the conclusion that an individual could be counted in Labour’s tally of total members, even if they had not paid a penny in membership fees for up to 18 months. Labour continue to deny this.