All five councillors from George Galloway's Respect party in Bradford have quit the party, accusing the MP of defamation and a lack of transparency.

Two of the councillors were suspended by Galloway and his aides in August after airing concerns to the Guardian about the alleged absenteeism of Respect's only MP.

At the time, Galloway justified the suspension of Mohammed Shabbir and Ishtiaq Ahmed by accusing them of "factional disloyalty" after they suggested he should stand down as MP for Bradford West if he wanted to run for London mayor.

All five councillors had been conspiring to seize executive power, he claimed. He later wrote a blogpost accusing them of stabbing him in the back after being elected "on my coattails".

Galloway labelled his landslide victory in a byelection last March as "the Bradford spring". The five councillors were elected two months later.

In a statement released on Friday morning and signed by all five councillors, Alyas Karmani, a youth worker and imam who acts as the Respect group leader on Bradford council, said senior party officials had failed to address legitimate concerns about the "unwarranted" suspensions.

The councillors had asked Galloway and the party for a "full and unconditional retraction" of what they called "defamatory statements and allegations made against our group of councillors collectively and individually". But none was forthcoming.

Despite leaving Respect, the five say they will continue to serve as councillors.

The councillors were angry after Galloway accused them of trying to destabilise Respect in the city by "openly conniving" with his former secretary, Aisha Ali Khan, and a Metropolitan police officer, Afiz Khan, who are soon to stand trial for data protection offences.

The councillors said in August that the allegation was baseless and unfounded and "symptomatic of a culture within the party that seeks to marginalise and excommunicate party members who raise legitimate concerns in relation to the operation and future development of the Respect party in Bradford".

Since mid-August the councillors have been operating as independents, trying to resolve their differences with the Respect leadership, said Karmani.

He blamed "certain gatekeepers" in the party for a lack of "transparency, accountability and equity" and that since discussions have failed to find common ground the group had no choice but to resign with immediate effect and carry on as independent councillors.

He added: "Regrettably these discussions have failed to find common ground as senior Respect officials have shown a disregard to address our legitimate grievances and we have been unable to resolve our issues of difference. After much deliberation this has left our group no choice but to fully resign from the Respect party with immediate effect and henceforth we will continue to operate as a group of independent councillors for the remainder of our term. This decision has not been made lightly and we are saddened that certain 'gatekeepers' involved in Bradford Respect appear to have no interest in transparency, accountability and equity."

According to the statement, when Karmani informed Rob Hoveman, Galloway's parliamentary secretary, that the councillors were all resigning as of Thursday night, Ahmed and Shabbir received an email from Ron Mckay (the acting secretary of the Respect party and a longtime friend of Galloway) that they have been dismissed from the Respect party as of 24 October 2013.

"This action only reinforces our views that decisions are made with complete disregard and contempt for any due process and are motivated by self-interest and not in the interest of constituents and the people of Bradford," said the statement.

"We find this particularly disturbing given that since being suspended on 13/8/2013 there has been no formal allegation put to them, no description of any processes, no interview and no opportunity for the two councillors to challenge the allegations made against them and there seems to be no collective endorsement for this decision from the Respect National Executive Council."

The statement is signed by Karmani, Shabbir, Ahmed, Faisal Khan and the Respect deputy group leader, Ruqayyah Collector, who used to be employed by Galloway as a case worker in his constituency office.

In a statement responding to the councillors' resignation, Respect said: "This is not about principle or policy, but self-interest and a naked attempt by the five councillors and one ally to control the party in Bradford.

"They proposed a constitution which would have given them absolute power in the party in the city … Their visibility and impact in the council chamber has been virtually nonexistent. If they had a shred of principle they would now resign their council seats and stand again in their new colours."

Earlier this week, Galloway was criticised by the leader of Bradford council after giving an interview in which he allegedly admitted preferring fighting elections to serving as an MP. According to the Evening Standard, Galloway said he was considering standing down as an MP because the House of Commons was "98% tedium". He reportedly said: "I'm interested in running for the Mayor of London in 2016 but I haven't decided ... I like elections more than I like serving."

Dave Green, the Labour leader of the council, accused Galloway of having "shown a contempt for all those people who voted for him last year".

Next week, the supreme court will decide whether to order the Charity Commission to release its investigation into the financial affairs of the Mariam Appeal, which was set up by Galloway. In 2007, the commission published a report about the charity that claimed it had received donations from "improper sources" connected with the Iraqi Oil for Food programme, set up while Iraq was subject to UN sanctions during the Saddam Hussein regime.