Sohan Singh was renting out some of the 28 properties in a block of flats in the north of Glasgow, which he bought from the city council for just £1 around 10 years ago.
However, just over a month before the local elections a few weeks ago, neither the flats nor the landlord were registered with Glasgow City Council –despite having tenants for at least a year.
He only registered after the intervention of a whistleblower led to officials pursuing him.
Rogue landlords risk being fined £50,000 if they do not register with councils. Last October, when Glasgow launched its latest crackdown, Mr Singh was one of around 6000 who had failed to lodge their details.
A local housing association also complained to public spending watchdogs that housing benefit was being paid to Mr Singh in a publicly owned property for which he had not paid.
Mr Singh, who counts Shadow Defence Secretary Jim Murphy, George Galloway, Mohammad Sarwar and ex-council leader Steven Purcell as friends, owns the Bombay Blues restaurant and Artto and Lorne hotels in Glasgow. Although jailed in 1999 for an alleged duty-free tax scam he was released on appeal.
Earlier this month he became a Labour councillor for Springburn and last week was given the civic honour of being appointed a Baillie of Glasgow.
But just one month before the local election, and several months after he became an official Labour candidate, Mr Singh had not registered the flats.
Emails show he requested the relevant documentation on March 28 after being contacted by council enforcement teams.
Landlord registration is a requirement of the Anti-Social Behaviour (Scotland) Act 2004 and failure to do so carries a maximum penalty of £50,000.
With 28 flats, he would have to be registered as a professional landlord, subjecting him to fit and proper person tests, health, safety and fire inspections.
The city council was aware the flats were occupied.
In May 2011, George Gillespie, the assistant director of land and environmental services, wrote to a local councillor, saying: "I can advise that the development is only partially completed. However, some flats are already occupied by tenants and difficulties have arisen with the temporary arrangements currently in place."
Even though Mr Singh only registered after being pursued, no retrospective action can be taken against him.
A council spokesman said: "There are tens of thousands of private landlords in Glasgow and the council works with them to ensure they are properly registered. In this case, we have worked with the company in question to ensure they are registered."
Mr Singh's company Kyleforth struck a deal with the council in 2003 that the flats would "rehabilitated" but the nature of the relationship changed several times over the years.
Apart from the £1 and a peppercorn lease, no money changed hands until last December when – nine years after the original deal – the council received £294,000.
Other documentation acquired by The Herald reveals unease from local housing associations on why they were overlooked when the properties were made available by the council.
Kyleforth secured the block because its director, Papinder Gill, a relative of Mr Singh, had a long-lease on the chip shop at the base of the block of flats
Health and safety complaints during the renovation and about the state of the development were also made, as well as concerns over the blight on the wider area caused by incompletion of the project.
When The Herald visited the properties this week pigeons and rubbish bags were clearly visible in at least one close.
In mid-2010, Mr Singh contacted both Blochairn and Spire View Housing Associations and asked if they would act as letting agents for the £500-a-month flats. Both refused.
The Herald contacted Mr Singh's home, restaurant and hotel but he did not return our calls.