The Acorn union has expelled an individual from its organisation after a man attempting to join its Manchester branch was sent two Instagram messages saying “no time for Zionists” and “we are a pro-Palestine organisation”.

The renters’ union, which conducted an internal investigation when it was alerted to the messages on Sunday, expelled the person — who has not been identified — after a national board meeting on Tuesday evening, and offered a profound apology to the recipient of the messages and the Jewish community.

Acorn bills itself as “a community-based union of working class people — tenants, workers, residents”, which fights to give low in-come communities a better life.

The man, whose Instagram profile clearly shows that he is Jewish — his photo features an Israeli flag and he uses Hebrew — had attempted to join Acorn after seeing a Manchester city centre demonstration on behalf of renters. He said: “I am a renter myself and I wanted to give support and also get some protection”.

But when he received the two messages in rejection, he told his friend Stephane Savary, the national vice-chair of the Jewish Labour Movement (JLM) and the north-west regional chair of the organisation.

Mr Savary challenged Acorn on Twitter, noting that not only had those who sent the rejection known his friend was Jewish, but that they had gone on to block him on Instagram. They had also blocked the man’s sister.

On Tuesday night the union issued a profound apology “for the upset and offence caused” to its Jewish members and the wider Jewish community.

It described the messages as unequivocally antisemitic. “In no way do they represent the views of our organisation”, the union said in a statement, adding that it had taken the opportunity to overhaul its social media practices as a result of the issue.

The man whose application sparked the messages told the JC he had not expected such a swift result. He said: “I am mildly shocked that it all led to such a just resolution, but I am delighted nevertheless.”