Mika Hakkinen’s Formula One test comeback with McLaren could easily be dismissed as a headline-grabbing publicity stunt or just a former world champion having fun.

Indeed, some already have.

“It’s a cosmetic exercise,” former team boss Eddie Jordan told Reuters after the announcement that the Finn was driving in Barcelona on Thursday. “I cannot see any logic to it at all otherwise.

“It will take him so much time to understand about the car and all the different technology that he will need far more than one day.”

The Finn is 38, four months longer in the tooth than Ferrari’s now-retired Michael Schumacher, and the test was the double champion’s first since he left at the end of 2001.

Five seasons is an age in grand prix racing, a sport littered with drivers whose careers fizzled out in a fraction of that time.

The last time Hakkinen raced in Formula One, the car had a V10 engine behind him rather than the current V8s.

Young Spaniard Fernando Alonso, joining McLaren from Renault next season as a double world champion, had not so much as scored a point.

Sceptics may well doubt that Hakkinen can contribute anything much in such a short space of time, in an unfamiliar car at the tail-end of November and for a team who have two test drivers already in addition to a confirmed 2007 line-up of Alonso and British rookie Lewis Hamilton.

They may be wrong, however.

“A driver of Mika’s calibre and experience can only bring added value to our testing programme,” said McLaren boss Ron Dennis, adding that there were no plans “at this stage” for him to do further tests.

Mercedes, who are hoping Hakkinen will return for another series with them in the DTM German Touring car championship, will be happy anyway to see the Finn’s profile raised a couple of notches, as will team sponsor Johnnie Walker, who recently appointed Hakkinen their ‘ambassador’ to promote responsible drinking and safe driving.

However, Hakkinen hinted on Wednesday that there was more to it than that.

The man who came back on the radar when he turned up in Brazil for last month’s season-ender, and who has since twice spent time in the McLaren F1 simulator, told reporters that the test was “absolutely serious.”

Former Minardi team boss Paul Stoddart felt inclined to believe him.

“I don’t think that Ron and (Mercedes motorsport head) Norbert (Haug) are the types to play games,” he told Reuters.

“I think he (Hakkinen) is doing it for a reason. Don’t discount him, just because he’s a bit older. Imagine if Michael (Schumacher) has a couple of years out and then said he wanted to get back in the car. Nobody would laugh at that.”

Reuters