Unite, Britain’s biggest trade union, has denied claims that a senior official directly hired a former Labour candidate who was suspended from the political party for making antisemitic remarks.

Jennie Formby, a Unite regional secretary and favourite to be appointed Labour’s general secretary next week, was said to have recruited Vicky Kirby who claimed Hitler might be a “Zionist God” and that Daesh should attack Israel, to work in Unite’s south-east region.

The Independent quoted a Unite source who claimed Ms Formby would have had to approve Ms Kirby’s appointment.

Ms Formby, a long-standing critic of Israel, has not commented on the allegation, and has previously denied any accusations of antisemitism.

Ms Kirby had been due to stand for Labour in Woking in the 2015 general election, but was dumped as a candidate in 2014 after a series of offensive tweets were posted from her account.

One message claimed Hitler might be the “Zionist God”.

Another said: “We invented Israel when saving them from Hitler, who now seems to be their teacher.”

A third tweet read: “I will never forget and I will make sure my kids teach their children how evil Israel is!”

One post was used to ask why Islamic State forces were “not attacking the real oppressors, Israel?”.

Ms Kirby was subsequently suspended from the Labour Party, before being readmitted and then suspended again. It is not clear whether she is currently a member of the party.

She was hired as a temporary regional officer by Unite in the south-east region which Ms Formby currently leads.

A Unite spokesman told the Independent that Ms Kirby had apologised for her remarks and that “lay members and other officials” were responsible for hiring her.

He told the news site: “Vicky Kirby made appalling antisemitic remarks on Twitter for which she was rightly sanctioned by the Labour Party.

“She has repeatedly apologised publicly and privately for those remarks, which Unite condemn unreservedly. She has been fully reinstated into the Labour Party.

“Ms Kirby has never been an employee of Unite, although she did two months temporary organising work for the union after she had been reinstated into the Labour Party.

“Ms Kirby has consistently expressed her heartfelt regret about her comments and had attended training courses to assist with her wider understanding of the offence her remarks had caused.

“Such appointments are not the prerogative of the regional secretary in any case but are made following a procedure involving lay members and other officials.

“Any attempt to suggest otherwise is a smear against Jennie Formby, whose opposition to antisemitism is a matter of record. Ms Kirby has not been employed by Unite since.”

John Mann, the Labour MP who chairs the All-Party Parliamentary Group Against Antisemitism, told the Independent it was “hugely inappropriate” for Unite to have employed Ms Kirby.

He said Ms Formby should be asked about the matter by Labour’s NEC, which will decide who will be appointed as Labour’s general secretary on Tuesday.