Allies of Jeremy Corbyn have rejected fresh claims his handling of Labour’s anti-Semitism crisis has coincided with a big fall in party members.

Centrist campaigners renewed their attacks on the party leader as they alleged that total party membership had dropped markedly in recent months.

HuffPost UK has learned Labour sent out 506,320 ballots for its recent NEC elections, based on the number of members eligible to vote for seats on the ruling body.

The number contrasts with the 550,000 figure for total membership declared by party chair Ian Lavery over the weekend.

Allies of Corbyn firmly reject claims of major drops in numbers or any link to the anti-Semitism row.

They point out that NEC figures exclude those who either joined the party after a cut-off date of June 23, or whose membership fees were in arrears on that date.

In March-to-April this year the membership total stood at 546,110, and the new statistics have prompted moderates to suggest there has been a fall since the Jewish community’s protests erupted in the Spring. 

It’s unclear how many new members have joined since June, but the NEC ballot total suggests tens of thousands of people are in arrears and could soon cease to be members of the party unless they pay their subs.

One former party insider said around 20,000 members had been in arrears for more than six months, and would be deemed to have ‘lapsed’ and effectively left the party. Others in the party suggested a year’s arrears were allowed before any lapsed membership.

Supporters of Corbyn point to the way the party membership has more than doubled from its 200,000 figure under Ed Miliband, making Labour the largest political movement in Europe.

But Luke Akehurst, secretary of Labour First said: “The failure of the leadership to speedily tackle the anti-Semitism crisis, and the toxic culture of bullying and sectarianism the hard left has created are driving both new and old members out of the party.

“They are squandering the once-in-a -ifetime opportunity to create a mass membership, united and pluralistic Labour Party.”

Party sources told HuffPost the 506,000 figure was some way off the actual membership total, but stressed that new members and those in arrears were not eligible for NEC ballot papers.

Labour has never formally briefed a running total of its membership because of cyclical increases and decreases that are erroneously linked to claimed causes.

Before Corbyn’s leadership, the number of members in arrears was roughly 5,000 and the increase in those quitting by not paying their subscription fee could be simply a proportional reflection of a bigger party overall.

At the start of the anti-Semitism row, leaked weekly figures showed nearly 1,000 people had joined up and 180 had actively resigned since the Parliament Square protests on the issue.

HuffPost understands 32.5 percent of the members issued with ballots this year took part in the NEC election, which would be an increase on turnout compared to previous years.

The left achieved a clean sweep in the election, with Momentum-backed candidates taking eight of the nine seats and controversial activist Pete Willsman taking the ninth slot.