THE Labour leader of Glasgow City Council is to be investigated by the Major Crimes Unit over alleged misconduct during the £100,000 contest to redesign George Square, Police Scotland confirmed last night.

Gordon Matheson's role in the process is to be probed by the Major Crimes and Public Protection division following a complaint from the member of the public last week.

The complaint was directed to this division rather than that of the Local Policing West which covers Glasgow.

Headed by Assistant Chief Constable Malcolm Graham, major crimes is one of Police Scotland's three specialist divisions, and covers a wide range of cases, including people trafficking and sex offences.

The inquiry will be an early test for how Scotland's new single police force handles a high-profile, politically charged case.

Matheson, 46, remains in post despite taking a hard line with others caught up in controversy. In 2011, he sacked a Labour councillor who made a disputed remark about a child rape victim before a hearing into the claim.

And last year another Glasgow Labour councillor was suspended for eight weeks after using his niece's disabled parking badge.

The police development puts pressure on Matheson ahead of the Glasgow Labour group AGM on May 13, when he may face a leadership challenge. However, no rival has yet stepped forward.

The proposed £15 million overhaul of George Square has haunted Matheson since he announced the scheme was being abandoned just minutes after the judging panel rejected his preferred option and picked one he detested instead.

The fiasco cost taxpayers about £100,000 and architectural practices about £200,000.

Last week the Royal Incorporation of Architects in Scotland (RIAS), which ran the contest, lodged a complaint against Matheson with the Public Standards Commissioner, suggesting he repeatedly violated the Councillors' Code of Conduct.

Matheson faces claims of interfering in a legally defined procurement process, bias, attempted staff coercion and trying to "steer" the contest in favour of his preferred design.

The RIAS complaint included a statement from Kerr Robertson, who until his recent retirement was the council's lead architect.

Despite the design contest being governed by strict European Union law, Robertson claims he was told six weeks before the judging officially began that Matheson would choose the winner.

Robertson also claims he was told his job would be "to ensure the other jury members would fall into line with this".

In a car-crash interview with STV last week, a flustered Matheson agreed Robertson was "a public official of integrity". Matheson added he was "entirely confident" that he would be cleared of any wrongdoing. He also denied that there had been any breach of the rules.

The complaint to the police largely mirrors the one by the RIAS to the ethics watchdog.

It is Matheson's second brush with the controversy in less than six months. In December, police reported him to the fiscal after he allegedly performed a sex act on another man in a car near his home in Glasgow's South Side.

He apologised to his partner for "an affair", while prosecutors took no action.

The SNP opposition in Glasgow is now pressing for the council's internal audit team to investigate the George Square affair.

It has also tabled a motion for the next full council meeting on May 16 calling on Audit Scotland "to investigate whether councillors unduly influenced the procurement process" and is pressing council chief executive George Black to review procurement procedures.

SNP group leader Graeme Hendry said: "Gordon Matheson has been accused of some very serious offences and it is only right and proper they are investigated by all the appropriate organisations.

"It would seem those running Scottish Labour are the only people left who don't seem to think these accusations should be checked.

"Their failure to suspend or even investigate Councillor Matheson stinks of hypocrisy, and will leave many people wondering just what it would take for Labour to act."

A Police Scotland spokeswoman said: "A complaint has been received and has been forwarded to ACC Graham of Major Crimes and Public Protection."

Contacted by the Sunday Herald last night, Matheson declined to respond directly to the developments.

However, in a statement issued by the council on his behalf, he said: "I'm happy for this to be fully investigated. I will give whatever help the police ask me to, and am confident there will ultimately be a finding in my favour."