A senior official from Nigel Farage’s pro-Brexit party has been removed after the Guardian uncovered antisemitic and other offensive Facebook posts he made, two weeks after the party leader quit her role for similar reasons.

The party said Michael McGough, its treasurer, had made “unacceptable statements” and would no longer have any role in the organisation.

In some messages, McGough refers to Ed and David Miliband and Peter Mandelson as having “shallow UK roots” or being “devoid of UK roots” – seen as a common antisemitic trope about Jewish people.

A Facebook post saw McGough refer to a foreigner as “someone from a bingo bongo land”. In another, he said many survivors of the Grenfell Tower fire were “illegal aliens enjoying an amnesty”.

On 20 March the original leader, Catherine Blaiklock, resigned after the Guardian asked her about a series of deleted anti-Islam Twitter messages, in which she repeatedly retweeted far-right figures as well as sending her own offensive updates.

The Electoral Commission now lists Farage as the party leader. The departure of McGough means that two of the three Brexit party officers originally listed by the commission have now left.

McGough was previously a longstanding Ukip member. He was on the party’s national executive and stood for election as an MP three times in the Essex constituency of Brentwood and Ongar. Like Farage and Blaiklock he left the party over its anti-Islam stance under its current leader, Gerard Batten.

Despite this, one of McGough’s Facebook posts, from March 2017, refers obliquely to Islam potentially being a “fifth column” in the UK. “Perhaps a packet of bacon would act like garlic to a vampire but I doubt it,” he wrote. “If we had sharia law then surely most of the terrorist retards would be limbless as they all seem to have past criminal records for theft and violence.”

A string of posts from the same year use seemingly antisemitic insults against the Milibands and Mandelson. One calls David Miliband “son of an east European communist now milking it from a charity in New York and devoid of UK roots”.

Another message says: “The Miliband dudes and Mandelson have the shortest of roots. Transient folk they have no loyalty to the UK.” One reply by another user tells McGough he is on “slightly dangerous ground”. McGough replies: “True, but there is a valid point to be made even if it seems offensive. It is not dissimilar to Lord Tebbit’s cricket test.”

A post about Mandelson reads: “I resent being called racist by an old queen with shallow UK roots.”

McGough also posted a string of homophobic comments in the autumn of 2017, when there were two LGBT candidates vying for the then vacant Ukip leadership.

“I don’t want a skirtlifter for leader,” he wrote in one. A post a month earlier said: “With Queers Week on the BBC we are being bombarded with material to undermine our sexuality and procreation. I doubt the immigrant birth rates will be affected.” Another referred to a transgender politician who had been on BBC radio: “My, what a deep voice and what a lousy state broadcaster.”

The Brexit party statement said: “The Brexit party is saddened by the unacceptable statements made by Mr McGough. Taken together they mean that he cannot hold a position in the Brexit party.”

Marie van der Zyl, president of the Board of Deputies of British Jews, said the party “did the right thing” in parting company with McGough and Blaiklock. “The new party will need to institute rigorous anti-racist procedures and policies to ensure this doesn’t keep happening,” she said.

Ian Murray, a Labour MP who backs the People’s Vote campaign, said Farage’s new party seemed to be “vectors for nasty, vicious and ugly politics”.

He said: “The worst argument against a People’s Vote or the European elections has always been that they would encourage the far right. We should be fighting, not hiding from, the far right and their friends like Farage at every single opportunity.”