In the latest development in the government’s campaign against unions, charges against CFMEU heads John Setka and Shaun Reardon could be struck out by the Magistrates’ Court. The two face up to 15 years in prison over the escalation of a dispute with infamous construction firm Grocon.

Setka and Reardon, secretary and assistant secretary of the Victorian branch of the construction union, faced court on 3 November, accused of criminal blackmail against Boral executives. The charge lays a dangerous precedent. If the two are convicted, it will open up a new way to punish industrial militants.

Outside the Melbourne Magistrates’ Court, shop stewards wearing black armbands told Red Flag: “The black armband is because we’ve had five construction workers die in the last three weeks. It’s a marker of respect”.

No construction boss has faced criminal charges following a workplace death. One of the stewards described the injustice of it: “Deaths can happen anywhere, but a lot more happen on non-union sites. We are there to prevent all that. [Setka and Reardon] were sticking up for their members, and they got arrested for it. I don’t think that’s a criminal offence”.

The charges are the most serious to come out of the Liberal government’s royal commission into trade unions. They stem from a longstanding dispute between the CFMEU and Grocon over the construction company’s refusal to allow union-approved health and safety officers on its building sites.

Boral, a major building supply company, claims to have lost money out of the dispute, alleging that Setka and Reardon organised an industry-wide boycott of its products because of its refusal to cut its supply of concrete to Grocon.

The law may not have been willing to step in to prevent the deaths of workers, but the union allegedly was. And while the law can hand out injunctions and fines to those who stand for workers’ rights, the hands of those workers pour the concrete and set the frames for every building in Melbourne. Boral’s CEO complained to the royal commission that the CFMEU “has significant control of all large construction sites except Grocon sites and no law in Australia seems to be able to stop their racketeering behaviour”.

Royal commissioner Dyson Heydon responded to Boral executives’ desperate pleas for a way to persecute the union: “If anyone within Boral does have ideas for the future regulation of institutions so as to avoid this happening in the future, we’d be interested in seeing that”. Out of the commission, Heydon recommended charging Setka and Reardon with blackmail.

On Thursday, Setka’s barrister, Robert Richter, argued for the charges to be struck out, describing them as a “desperate attempt to criminalise behaviour that occurs within the context of an industrial dispute”. He told the court that secondary boycotts relating to industrial conflict are decriminalised by provisions in both Commonwealth and state laws.

The prosecution told the magistrate that the charges could not be struck, telling the Magistrate, “You are bound to proceed”.

If the charges are struck out, it would represent a victory over the government’s anti-union laws. Outside the court, a shop steward from a CBD site reflected on the possibility of losing the case: “If we’re going to get arrested for sticking up for our members, I’d be happy to get arrested every time. I think Johnny Setka, Shaun Reardon, and anyone else in the union would feel the same”.

The case returns to court on 9 November.