Jeremy Corbyn is facing claims of a stitch-up over the selection of candidates to fight the next election after the Momentum group endorsed a candidate for the Poplar and Limehouse seat in East London who has been investigated over antisemitism allegations.

Apsana Begum, who has been endorsed by Shadow Chancellor John McDonnell, sparked anger earlier this year after it emerged she had accused Tony Blair of spreading “Zionist propaganda” and shared a shared media post claiming Saudi Arabia’s leaders were “inspired by Zionist masters”.

She was also revealed to have circulated material by political activist Ken O’Keefe, who has faced accusations of antisemitism and of being a 9/11 conspiracy theorist in the past.

On Wednesday, Labour sources confirmed that Ms Begum, who once worked for Tower Hamlet’s disgraced mayor Lutfur Rahman, had been the subject of an investigation into her social media posts. 

It is understood Ms Begum faced no sanctions following Labour’s investigation.

On Monday it emerged that Ms Begum’s name was on the long-list of candidates selected to replace MP Jim Fitzpatrick, who is standing down in the safe Labour seat.

Local party sources say it is now “a certainty” that Ms Begum’s name will be placed on the short-list of candidates after she received the endorsement of the pro-Corbyn Momentum group, with which she holds a senior position.

But the moves have left local members fuming, with the popular Rachel Blake, a Tower Hamlets councillor and deputy mayor for planning and air quality, excluded from the long-list.

The most strongly anti-Corbyn candidate, Suzy Stride, is also expected to be knocked off of the short-list by party officials, as is Asman Begun, another popular Bengali activist but who is not seen as being as pro-Corbyn.

One local insider said: “It’s all being tied up for Apsana.”

Another Labour insider compared the situation in Poplar and Limehouse with that in Ilford South ,where a popular council leader, Jas Athwal, was suspended by the party only hours before the selection process was due to take place to find a replacement for the MP Mike Gapes, who quit in February.

It was claimed that Momentum activists in Ilford pushed for the suspension in order to put forward their own candidate. “The Corbyn leadership have clearly dropped any pretence there is no political interference in selection. Sikh’s (Mr Athwal) get suspended before selection processes, racists get their suspension lifted before selection processes,” said the source.

Labour sources claimed the probe into Ms Begum was concluded some time ago after the proper procedures had been followed.

Endorsing Ms Begum, Mr McDonnell said would be "a powerful voice for all communities in Westminster", adding she was a "dedicated socialist... who has worked with integrity and diligence to build a grassroots Labour movement".