There are, it turns out, two Kimi Raikkonens.

The public face of the 2007 world champion, who has returned to Formula 1 this season after two years in rallying, is of a monosyllabic, monotone, unsmiling figure, energised only the moment he steps into a racing car.

The one who emerges in private is very different - a talkative, jocular man, who can happily sit and shoot the breeze like anyone else.

As Lotus trackside operations director, Alan Permane has worked closely with Raikkonen since he joined the team last November.

Kimi Raikkonen has been perceived as cold and uncommunicative. Photo: Getty

The 32-year-old Finn, Permane says, "is happy to sit and talk, not only about technical stuff, but laughing and joking and talking rubbish with his engineers about all sorts of stuff".

He is just not interested in any of his dealings with the media and, unlike his rivals, doesn't bother to hide it.

Permane worked with Michael Schumacher and Fernando Alonso through the title-winning years with the team formerly known as both Benetton and Renault. He has been impressed with Raikkonen from the start.

Raikkonen first drove one of the team's cars at the Ricardo Tormo circuit in Valencia in late January. Straightaway the team knew they had something special.

He had not driven an F1 car since the 2009 Abu Dhabi Grand Prix, and had no experience of the Pirelli tyres he was using. Yet, after a single installation lap to check the car's systems were working, his first flying lap was within a few 10ths of a second of the fastest lap he would do over the next two days.

The good impressions did not go away.

Permane said, "He has never driven a car with a full load of fuel in it.

"We went from 30-160kg [of fuel load in Valencia] to show him that's the sort of difference you can expect - certainly from qualifying to race it's even bigger than that.

"We calculate the lap time difference the fuel load will make and his first lap was absolutely spot on that difference. That is impressive."

After that, Raikkonen did another 20 laps, each one exactly 0.1secs slower than the last - the lap time lost by tyre degradation.

There is a widespread belief that Raikkonen is as unforthcoming in his technical debriefs as he is in public, but that, too, appears to be a fallacy.

Lotus have found his comments in debriefs to be not only lengthy but very perceptive, too.

He was slightly quicker than new team-mate Romain Grosjean throughout pre-season testing, so it was a surprise that he was about 0.2secs slower than the Franco-Swiss semi-novice in the practice sessions in Melbourne.

Equally, the errors Raikkonen made on his qualifying laps that left him down in 18th on the grid betrayed a certain ring-rustiness, as well as perhaps the pressure he was feeling from Grosjean's pace.

In the race, though, something of the old Raikkonen returned as he fought back up from his low starting position to take seventh place by the end.

Clearly, though, there is more to come.

Raikkonen is not entirely happy with the feel he is getting from the Lotus's steering, but Permane plays down the significance of the problem.

"He's very particular," Permane says. "He knows what he wants and it's not quite to his liking. It's not a million miles away, but we'll get it there."

Raikkonen can drive perfectly well with the steering as it is, but the problem probably does mean that he is driving a little below his maximum.

The question now is, at what level is his maximum?

The reason Raikkonen left F1 in the first place was because he performed for Ferrari for much of 2008 and 2009 way below the level expected of him.

Ferrari, in fact, terminated Raikkonen's contract a year early and paid him not to drive in 2010 so they could bring in Alonso.

The Spaniard has since out-performed Felipe Massa, the man who generally had the better of Raikkonen from the start of 2008 until fracturing his skull in an accident in Hungary in July 2009.

Does this mean Alonso is that much better than Raikkonen? Or that Raikkonen in 2008-9 was a long way below his best? Or that Massa is not the driver he was?

No one knows for sure, but for Raikkonen's comeback to be considered an unqualified success he will have to be able to match his new team-mate's pace.

The fact Lotus have regrouped over the winter and produced one of the year's fastest cars only increases the pressure - it's not so bad to be beaten by a team-mate when you're battling to get into the top 10; but a very different matter when you're fighting for the podium.

That, it appears, is what Lotus are in a position to do.

"We screwed up with the car last year," Permane says, "and we know we've done a lovely car this year, not only aerodynamically, but we've done a nice package mechanically."

So pleased are Lotus with the new E20 that Permane says he "dared to compare it with 2005", when Alonso won the first of his two titles.

That is not so much a measure of Lotus's realistic hopes as a reflection of how much the drivers like the car, and how well it responds to changes.

Nevertheless, the team are confident they can keep up with the break-neck development pace of the likes of McLaren and Red Bull and hold on to their position.

For Raikkonen, the requirement now is prove that he can go with them. So far, the signs are positive.