Labour has agreed to check the voting history of new members and supporters after it came under pressure from the leadership campaigns of Andy Burnham, Yvette Cooper and Liz Kendall to step up its efforts to weed out suspected infiltrators.

The party reversed its decision not to use its internal canvass data that reveals people’s voting histories, after three out of the four candidates raised concern about the robustness of checks on new members and supporters.

It also backtracked on its previous refusal to publish the breakdown of how the three different sections of the membership end up voting – the 293,000 members, 148,000 supporters signed up through trade unions, and 113,000 registered supporters who paid £3 to take part.

The Guardian revealed last week that a meeting of the party’s procedure committee decided not to use the canvass data to conduct extra checks against legal advice on how to protect the contest against legal challenge.

But on Tuesday, the campaigns of Burnham, Cooper and Kendall all demanded that voting history should be checked in suspect cases, as it emerged that 56,000 new applicants were duplicates or not on the electoral roll, while around 3,200 were found to be supporters of other parties.

Labour would not reveal exactly how it would use the voting history of new members and supporters to determine whether that person genuinely supports the aims and values of the party.

But it is understood that people will not be automatically excluded based on how the canvass data says they have voted in the past. It is more likely that a new supporter found to have voted Conservative, Green, Liberal Democrat or for another party would be telephoned by party HQ to check whether they have just changed their political persuasion or are in fact an infiltrator.

A Labour spokesman said: “The procedure committee met today to receive feedback from yesterday’s candidates’ briefings. The following decisions were made: canvassing material will be used to inform work to establish whether participants are supporters of the aims and values of the Labour party.

“That as well as the one-person, one-vote overall result, the results of the leader and deputy leader elections will be broken down by party members, affiliated supporters and registered supporters. No other breakdown of the results will be provided.”

Labour has revealed that phone calls to samples of new sign-ups found a small proportion – 4.4% of registered supporters and 2.4% of union-affiliated supporters – were actually backers of other parties.

While Corbyn is still clearly the frontrunner in the contest, supporters of the other campaigns believe undiscovered infiltration could make a difference in a tight contest.



A source in one campaign team said there was particular concern that the party had only managed to identify the social media profiles of 45,000 people, meaning verification is largely reliant on MPs and local parties checking to see if they recognise any of the names on the voter list as prominent supporters of other parties.

Corbyn has dismissed fears about Tory infiltration of the process as a “lot of nonsense” and suggested that people barred from the contest should be given a right of appeal.

The move to exclude people deemed to be supporters of other parties has been condemned by many of those affected on social media as a Labour purge.



It emerged on Tuesday that Mark Serwotka, the leader of the PCS civil service union, is one of those who has been prevented from voting as a registered supporter.