Some pretty tough noises are starting to come out of Turin regarding Fiat’s potential future investment in its plant near Naples.

CEO Sergio Marchionne is turning the screw on his myriad unions in an attempt to secure updated working practices in exchange for massive new investment in the new Panda model at the Pomigliano d’Arco factory.

Those unions – replete with a bewildering flurry of acronyms FIM, ULIM, FISMIC and UGL et al – have all met the boss in a bid to thrash out new ways to squeeze productivity improvements.

All apart from one. Extraordinarily, FIOM, which claims to be the largest union in Fiat, did not meet management last week. A statement from Fiat noted: “A further meeting with FIOM, which had communicated that it was unable to attend, has been set for 4 June.

A casual observer might just have thought FIOM would have made the effort given so much is at stake and if the top union brass couldn’t make it, at least send someone. Fiat casually dropped in the fact that regional representatives of FIM, UILM, FISMIC were connected via video link from Naples, so they managed.

And Fiat is pulling no punches here. It’s pretty much making a straight connection between the fact unless its tricky unions agree to changes in work practices such as operating weekend shifts, then the Panda will not be built at Pomigliano d’Arco.

The manufacturer has made some bold claims the site could see production levels soar from its current 40,000 annual units to a massive 300,000 vehicles. “That plant has never made that many cars,” a Fiat spokesman told just-auto.

Marchionne wants the unions on board, he’s not unilaterally going to impose draconian new working methods – perhaps mindful of previous militancy.

But he has a pretty impressive carrot and stick to wield to get the unions on his side.

Transferring Panda production will be a huge boost to the region and Marchionne is pretty much saying the future of Pomigliano is at stake should a deal not be struck.

The CEO is also firing a warning shot across the bows of his other plants in Italy by noting: “To guarantee a future for Pomigliano d’Arco and Fiat’s manufacturing activities in Italy, it is essential that plants be more efficient and more competitive.”

That’s a pretty important meeting for FIOM to be at in Turin.