WA’s former road safety boss claims he was threatened with criminal charges if he refused to cough up information about the Barnett government’s deal to sponsor the Western Force rugby union club.

In a letter of complaint to the public service watchdog obtained by The Weekend West, former road safety commissioner Kim Papalia attacked the McGowan Government’s probe of past spending and projects, suggesting special inquirer John Langoulant lacked qualifications to lead the inquiry.

Mr Papalia, a former high-ranking police officer and brother of Government frontbencher Paul Papalia, was sidelined after threatening legal action to avoid handing over material on the Barnett government’s eleventh-hour naming rights deal with Western Force.

The $1.5 million sponsorship of Western Force, announced just 24 hours before election writs were issued, is one of dozens of Barnett government projects and decisions being investigated by the Langoulant inquiry.

In his letter to Public Sector Commissioner Mal Wauchope, Mr Papalia said Mr Langoulant repeatedly threatened to charge him during examination for refusing to disclose material, which Mr Papalia said could have been subject to public interest immunity.

“In doing so, Mr Langoulant capriciously disregarded the lawful and procedurally correct methods for consideration of such material,” Mr Papalia said.

He noted that Mr Langoulant held only a Bachelor of Economics from the University of WA.

Mr Papalia said it was ironic the Western Force decision was being targeted for acting in haste, noting the Langoulant inquiry was itself “over budget, over schedule and arguably underdelivering in relation to public value”.

He said he was “perplexed” when arbitrarily dismissed by Mr Langoulant during the inquiry for commenting on lessons learnt in a case in which road safety ambassador David Wirrpanda was caught drink-driving in 2015.

Mr Papalia said he subsequently became aware Treasurer Ben Wyatt made a $2 million funding allocation to the Wirrpanda Foundation in August.