The bombshell departure that will test Mercedes' depth

Just as the history books credit Ferrari's greatest years of Formula 1 dominance to a dream team made up of Michael Schumacher/Jean Todt/Ross Brawn and Rory Byrne, so too will the current Mercedes era of six straight drivers and manufacturers' world championship doubles be linked to a core group of individuals.

The Silver Arrows success story hasn't finished yet though, so it's hard to say who the exclusive members of its club will be. But, for now, you would be hard pressed to argue against Mercedes engine guru Andy Cowell being guaranteed a spot in there alongside Toto Wolff, Niki Lauda and Lewis Hamilton.

While Cowell may not have the huge public profile of other members of the outfit, his contribution as the head of Mercedes' High Performance Powertrains division that has delivered brilliant engines year-after-year since the turbo hybrid era began in 2014 has been one of its core strengths.

So when the news emerged that, back in January, Cowell had decided he no longer wanted to carry on his current role, there could be no hiding from the potential significance of the moment.

Yes, it's too dramatic to suggest that Cowell stepping away will mean the end of the Mercedes F1 steamroller. But it will almost certainly be a disruption.

For however much Cowell has ensured that there is a succession plan in place, and will help guide Mercedes during this interim period to help his replacements get up to speed, his absence from the project in the long term will be felt.

From getting his hands dirty on understanding the individual components of the engine, to motivating and inspiring the teams of engineers operating underneath him at Brixworth, Cowell was an omnipresent force in the Mercedes operation who cannot simply be pulled out and replaced without anyone noticing.

Cowell's career has been one of great success. He started at Cosworth on its graduate scheme straight from university and swiftly progressed through its departments to begin his focus on F1 engines. By 1998 he led the engineering project group on the CK engine that helped Stewart win its only grand prix in 1999. He then enjoyed a brief spell at BMW Motorsport at the start of its F1 foray with Williams, before returning to Cosworth in 2001.

In 2004 he joined Mercedes-Ilmor to help work on its V8 project before eventually taking charge of programme leadership of all engine and powertrain projects - including the early hybrid experiments with KERS (Kinetic Energy Recovery System).

When Mercedes ramped up its F1 efforts knowing the opportunity that the 2014 turbo hybrid rules offered, it was clear that Cowell was the man to lead it on the engine front - and he was duly appointed as HPP managing director.

Cowell was fascinated with pushing the envelope further with each and every aspect. To him, anything that his engine department could bring to improve overall performance was something to be enthused about

The on-track records speak for themselves: with Mercedes having been unbeaten to a world championship since then. It was apt that it should be Cowell who was chosen to represent Mercedes on the rostrum after Nico Rosberg's victory in the first grand prix of the new era in Melbourne.

And, although the current turbo hybrid engines had not proved to be a big hit with fans - many of whom still lament the demise of the screaming V8s - they have filled Cowell with tremendous enthusiasm and huge pride.

Whenever you got Cowell talking about the progress being made with the engines, in terms of efficiency and durability, you could see the sparkle in his eyes. Sure, such aspects of engine performance may not be as sexy as talking about 1000bhp motors, or turbo boost being turned to the max so there is wheelspin in sixth gear.

But when Cowell helped Mercedes deliver the most efficient racing car engine in history - with thermal efficiency that broke the 50% barrier on the dyno in 2017 - it was a genuinely important moment for F1.

Throughout his period at Mercedes, Cowell was fascinated with pushing the envelope further with each and every aspect. To him, anything that his engine department could bring to improve overall performance - even if it meant simply making the same component last longer - was something to be enthused about.

I recall at the FIA Awards Gala in Paris last year that Cowell couldn't wait to tell me that he had received some figures about the distance completed for all the components on Lewis Hamilton's powerunit that had dominated the Abu Dhabi Grand Prix.

Each element (including the MGU-K that had done 7281km), had done more distance than the race winning Toyota from last year's Le Mans 24 Hours. Having helped create the most durable engine in motorsport, it was an achievement that made him especially proud.

From a personal perspective, Cowell had that amazing knack of being able to explain these most complicated of modern powerplants to people like me, who aren't engineering geniuses like him. It says much about his ability to engage and entertain that one of my favourite memories from the many Monaco Grands Prix I've been to came from a typically mad Thursday night party on a yacht.

I bumped into Cowell and we spent several hours talking about F1, the technical challenges, the engineering brilliance, life, the universe and everything. I learned a lot about engines that night. Start him on the topic of his job, and there was never any stopping him.

While some in F1 have pined for turning back the clock and ridding the championship of the current turbo hybrids, Cowell is certainly not one of them. He sees a strong future for hybrids - even amid the boom in electric powerplants.

In his view, F1 just needs to pull up its socks and do a better job in shouting from the rafters about its powerunits, rather than letting the world think that batteries alone are the answer.

"F1 engines are a marvellous marriage of high efficient, internal combustion engine technology and high voltage high power electric machines," he told me last winter. "Their batteries are 800 plus volts.

"We've got this dull 'ERS' title, but it's an energy recovery system: so it's waste energy that is being used. We're not charging the battery up from a diesel generator before we start the race. That battery is being charged by waste exhaust gas energy and waste kinetic energy in the car.

"That is a better story than Formula E, so there is loads more we can do. Loads more."

The same is true for Cowell's career too. Mercedes isn't the end of the road for his success.

Wherever he goes in the future, he will carry his brilliance with him. There is loads he can and will do yet.