Green Party leader Zack Polanski is facing a formal standards investigation after he admitted failing to pay council tax while living on a narrowboat for three years in east London. 

Earlier this month, Mr Polanski was referred to the Greater London Authority's (GLA) monitoring office by both the Conservative and Labour parties regarding his council tax arrangements. 

Now, the authority's watchdog has confirmed they have received the complaints and will assess whether or not to launch a formal investigation into if the Green leader breached standards by failing to pay the set rates. 

The standards officer wrote they are treating the parties' correspondence as a 'formal complaint under the GLA's standards regime', in email records seen by The Times.

They said a monitoring officer will be required to consider complaints regarding 'the conduct of elected members,' and this is in 'accordance with the approved GLA member code of conduct complaints procedure'. 

They added: 'This will now be considered in accordance with the authority's established procedures, including an initial assessment of whether an investigation is required.' 

Mr Polanski, 43, was registered on the electoral roll at a building in a marina where he kept the narrowboat - called The Olympian - and had post delivered there and had laundry collected.

The boat was recently advertised for sale for £100,000, but the notice was mysteriously pulled after the Left-wing leader's council tax arrangements were called into question. 

Despite the ad referring to the narrowboat as his 'amazing home' over the past three years, Mr Polanski initially maintained he had not lived there permanently.

This admission means the Green Party lied to the Press when officials falsely claimed that Mr Polanski - who campaigns for punitive wealth taxes on high earners - only stayed on the boat 'occasionally'.

The Green leader has since come under fire by his political rivals. 

He was reported to City Hall authorities by Labour chair, Anna Turley, earlier this month, who questioned if he had broken the law by failing to declare his council tax arrears.

A letter, which was seen by the Daily Mail, said: 'Mr Polanski appears to have failed to comply with the provisions of the Local Government Finance Act 1992 while holding elected office as an Assembly Member.' 

Neil Garratt, the leader of the City Hall Conservatives, also said: 'Zack's had plenty to say about other people not paying tax, but now it seems he was voting on Londoners' council tax bills without paying his own.

'No politician is above the law, no matter how good an actor, or ignorant of the law they may be. 

'His story keeps changing, but if he's broken the law then City Hall authorities should report him to the police and Scotland Yard should investigate, as the public will want answers.'

Tory chairman Kevin Hollinrake additionally weighed in, adding that Mr Polanski was guilty of 'staggering hypocrisy'. 

He said: 'Zack Polanski cannot lecture families across the country about paying more when he apparently wouldn't even meet his own obligations in full. 

'The British public will see this for exactly what it is. One rule for Zack Polanski, another for everyone else.' 

Government guidance states that council tax is payable if a boat is a person's 'sole or main residence'.

But analysis by tax lawyer Dan Neidle, from Tax Policy Associates, found that Mr Polanski and his partner's boat was not registered for council tax at the marina - despite another boat there previously being registered.

The boat and mooring would be rated as Band A, meaning Mr Polanski could owe a total sum of council tax for three years of about £4,000, according to the analysis. 

Mr Polanski has since apologised for the 'unintentional mistake' and said he had 'immediately taken steps' to pay any outstanding amount.

In a statement, a Green Party spokesman said: 'Until relatively recently, Zack was living on a houseboat, which came with its own unique practical circumstances and considerations.

'He has immediately taken steps to pay any council tax he may be found to owe. Zack apologises sincerely for the unintentional mistake.

'For security reasons, we do not comment publicly on Zack's address. There have recently been two serious incidents which have been reported to the police and are under investigation.'

The GLA added: 'The monitoring officer has received two complaints that Zack Polanski breached the Greater London Authority's members' Code of Conduct. 

'Those complaints are being considered under the GLA's usual process. It would not be appropriate to comment further while this process is ongoing.'