Zack Polanski has been cleared by an ethics inquiry looking into complaints that he did not pay council tax while living on a houseboat.

A report by the Greater London authority’s monitoring officer found that the circumstances of the Green party leader’s living arrangements were beyond its scope and he had therefore not breached the code of conduct for London assembly members.

The complaints from Labour and the Conservatives alleged that Polanski had breached the requirements of the ethics code because he had not paid council tax while living on a houseboat in east London from 2022.

Polanski, who previously apologised for the “unintentional mistake”, revealed in his evidence to the monitoring officer that it had still not been established whether any tax was due and that the site of the boat fell on the border of two local authorities. As part of the inquiry, he told the monitoring officer that he had “personal experience of financial hardship and housing insecurity”.

He previously said he had not been living at the marina full-time but at another address as a lodger, before it emerged that he had occupied the boat for a couple of years before moving to a house.

In his witness statement, Polanski he said he had never had any intention to “evade council tax, avoid legal obligations or obtain any improper financial advantage” and it remained unclear whether he had actually failed to pay the proper tax.

“Any failure to appreciate the position arose solely from a misunderstanding of what was required in relation to an unusual and unconventional living arrangement,” he wrote.

“Having lived through periods of economic difficulty on a limited income, I understand first-hand the challenges faced by many Londoners,” he wrote in his statement. “My previous living arrangements reflected those circumstances rather than any attempt to avoid financial obligations.

“Whilst I accept that greater care could have been taken in understanding the practical implications of my unconventional housing arrangements, I strongly refute suggestions that my honesty or integrity should be called into question.”

Polanski also revealed that he had lived for five years as a property guardian, occupying an otherwise vacant building under licence in return for modest fees.

“This was one of the few affordable housing options available to me in London during a period marked by economic uncertainty, austerity measures and significant cost-of-living pressures,” he said.

“Under those property guardianship arrangements, I paid a licence fee to the relevant provider and, as was my understanding and experience throughout that period, utilities and council tax liabilities were managed and covered through those arrangements. Whilst unconventional, this became my normal experience of housing administration and associated household outgoings.”

He said that when he moved to the narrowboat in August 2022, he believed that council tax was included in the moorings fees “given the nature of the arrangement, my previous experience of property guardian accommodation”.

He added: “I readily acknowledge that I did not undertake further enquiries at the time regarding the specific council tax implications of living on a narrowboat. This is why I have already unreservedly apologised for that unintentional mistake.”

Polanski also raised concerns that the complaints were politically motivated and said they had been promoted under the guise of public interest yet appeared to aim to advantage his opponents.

The Green party said: “The monitoring officer for the Greater London Authority has conducted an independent inquiry into the complaints made against Mr Polanski and decided to take no further action. We therefore consider this matter closed.”

Neil Garratt, the Conservative assembly member who originally complained about Polanski, said his actions had shown a “cavalier attitude” to establishing whether tax was due.