THE head of bus operations at Strathclyde Partnership for Transport has sent shockwaves through the industry after quitting suddenly, less than two years after he was hired amid claims of a "jobs for the boys" recruitment process.

Ronnie Park is understood to have resigned out of the blue last Friday for reasons that remain a mystery.

Furniture was cleared from his office at SPT headquarters in Glasgow on Monday and a memo was distributed to staff on Wednesday confirming that the former managing director of First Glasgow would not be returning to his post at the quango, where he is thought to have been earning around £90,000 a year.

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Industry sources have been left stunned by what is being described as a "sudden departure", with friends and colleagues who saw the executive in recent weeks saying he gave no hint of unhappiness in the job.

One source said Mr Park had appeared to be "in fine form" when he attended the most recent meeting of the Bus Stakeholders Group a fortnight ago.

The source said: "He seemed happy, he wasn't harbouring any ill feeling towards SPT or anything like that. I can't think of anything that would have led him to quit."

Another source said there was no suggestion that Mr Park had departed "under a cloud".

Malcolm Balfour, an SNP councillor for Glasgow and one of SPT's elected members, said he was sorry to see Mr Park leave.

Mr Balfour added: "I've known Ronnie for a number of years and I have always found him more than capable. I think he'll be missed by the organisation."

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Mr Park was hired by SPT in January 2015 to head up its bus operations division.

The post had been left vacant since the height of the SPT expenses scandal in 2010, although the job was advertised in 2011 but never filled.

However, there were suggestions from those inside the organisation that the recruitment process was subsequently tailored to ensure that Mr Park was the only suitable candidate when the post was re-advertised in 2014, coinciding with the end of Mr Park's gardening leave from First Glasgow.

Mr Park was the only person interviewed for the SPT executive position. At the time, SPT said the job was advertised widely but that "only one applicant met the essential criteria specified in the advert and therefore qualified for interview".

Critics said it pointed to a "jobs for the boys" culture since Mr Park would be joining his friend and former colleague, Eric Stewart, on the SPT board.

Mr Stewart had previously served as managing director of First Glasgow for a number of years, working alongside Mr Park who was then operations director and later deputy managing director.

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Mr Stewart subsequently moved to SPT while Mr Park went on to serve as managing director of First Glasgow from 2010 until July 2013, when he was placed on "indefinite gardening leave" for undisclosed reasons.

Mr Park's departure also comes four months after an SPT report caused controversy with some commercial operators by linking a "significant and worrying fall" in bus patronage across the region to a "market failure".

A spokeswoman for SPT confirmed that Mr Park has left the organisation.

She added: "We would like to thank Ronnie for his time at SPT and wish him well for the future."