Labour has suspended both its constituency parties in Newham.
The Recorder understands London Labour notified members of the decision to suspend East Ham and West Ham constituency Labour parties (CLPs) in an email sent today (March 12).
The party's ruling National Executive Committee (NEC) made the decision.
Candidate selection by the local authority to find a third councillor to represent East Ham Central ward has been postponed by the party.
The Recorder believes London Labour could put forward a candidate of its own choosing in time to contest the by-election.
West Ham CLP secretary John Saunders is also considering his position, the Recorder understands.
A national Labour spokesperson said the party takes all complaints extremely seriously and they are fully investigated in line with its rules and procedures with appropriate action taken.
The email from London Labour, seen by the Recorder, states: "The Party has recently been in receipt of a significant number of serious allegations regarding the conduct of Labour Party members and membership recruitment practices in Newham.
"The allegations are wide ranging and supported by a considerable amount of evidence.
"Furthermore, we also understand that allegations of electoral fraud are being separately investigated by the Metropolitan Police."
However, a Met spokesperson said while the service received an allegation of electoral malpractice in Newham in August, its assessment concluded a police investigation was not required.
According to the email, an analysis of membership data in East Ham and West Ham CLPs shows "irregularities" in new member sign ups "over a sustained period".
London Labour rules out providing more details, but describes the "irregularities" as "significant".
The email states: "Due to the seriousness of the allegations, the NEC has agreed to suspend both East Ham and West Ham CLPs with immediate effect."
The party is carrying out its own investigation as well as an audit of members in part to uphold Labour's reputation and constitution.
During the suspensions neither CLP can hold meetings or engage in party business.
A "roadmap" which would outline plans for both CLPs to return "to normal business" is due to be agreed by the NEC "in due course", the email ends.
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