'Put up, or shut up,' is essentially Steve Nielsen's mantra as he hits out at manufacturers questioning Mercedes' legality.

"They've got their right to protest I suppose," the Alpine MD told reporters in Bahrain. "We go to Melbourne, and if they really feel that strongly, then put some skin in the game and do something about it," he added.

"I don't know whether the FIA will express a view on this before Melbourne," he continued. "I kind of hope they do because I kind of hope the story of Melbourne isn't about compression ratios."

It's somewhat ironic coming from Alpine, who, aside from ditching the engines of their parent company for the Mercedes unit, in their various guises have not merely pushed the envelope but often ripped it apart.

Looking ahead, Nielsen, fears what sort of precedent is set should the rival manufacturers prevail.

"The more fundamental thing for me is the way we're going about it," he said. "If we're saying that a very clear written set of regulations can be challenged in this way, then what else is off limits? Everything's up for discussion.

"People invest an awful lot of time and money... and particularly money into this, in good faith," he continued. "And if suddenly everything can be challenged, then I think that's a whole new world which we've not been in before.

"You could say I'm biased," he admitted, "because we've got a Mercedes engine in our car, but do we really want a sport where clearly written stuff can just be challenged because people fancy doing it? That's for the FIA to answer."

Meanwhile, as if on cue, George Russell, who certainly has skin in the game, followed the lead of his boss, Toto Wolff, in suggesting that (legal or not) Mercedes is playing catch-up to the real benchmark, Red Bull.

"I don't think anybody should really be looking at us," he said, "you should be looking at the most competitive car on the grid which right now is the Red Bull.

"They're not just a small step ahead," he continued, "you're talking in the order of half a second to a second in deployment over the course of a lap, so it's pretty scary to see that difference.

"Red Bull have always delivered a very good car over the past 15 years even when they didn't have a great engine, so this test has been really eye-opening for a lot of us.

"The truth is Red Bull, in Barcelona Day 1, hit the ground running and were well ahead of all of their competitors, so ourselves, Ferrari and the others. Day 1 here in Bahrain again, they sort of knocked it out of the park, so they are, at the moment they're very much a team to beat, and it's quite straightforward when you have three days of testing in the same location to make those improvements, but when you get to Melbourne and you've got three hours of practise before qualifying, based on what we've seen in Barcelona and Bahrain Red Bull are going to be ahead so yeah, we've got work to do."