Michael Schumacher is a "tragic ex-hero" who should return immediately to retirement.

Michael Schumacher is a "tragic ex-hero" who should return immediately to retirement.

That is the view of Mika Hakkinen, who was once named as the only rival the seven time world champion truly feared.

The Finn has issued a harsh critique of Schumacher in a column for the Munich newspaper TZ, despite the pair always referring to each other with the greatest of respect.

"Michael is for me now a tragic ex-hero," 42-year-old Hakkinen wrote after the final race of Schumacher's comeback year; the only full season in the German's entire career that did not net even a single podium.

"I ask myself why on earth he got back into the cockpit. There is the most successful man in motor sport driving down in the pack and making a ridiculous mistake in Abu Dhabi that almost cost him his life," he added.

Hakkinen is referring to his spin on the first lap that resulted in Tonio Liuzzi's Force India riding over Schumacher's Mercedes and almost striking his head.

Afterwards, Schumacher admitted the incident gave him a fright and a trip to the medical centre, but has pledged to return in 2011.

But "What a tragedy this would have been for the Germans -- and on the day of Vettel's triumph," said Hakkinen.

"What has the man who has won more than anyone else still to prove?" Hakkinen wondered. "In my view, he is dismantling his own legacy bit by bit.

"And I see it making no difference whether it is for technical reasons or because he can no longer keep up with the boys."

Hakkinen said he can understand Schumacher's urge to return to action after three years of retirement.

"After three years I returned to the cockpit myself -- for Mercedes in the DTM," he recalled. "And I also had to recognise that even as a formula one world champion, there are no gifts for the older ones.

"I won only three times more," said Hakkinen.

"You can neither stop the wheel of time, nor turn it back," he insisted.

"Personally, we were never close friends because he always came across, to me anyway, a little bit too arrogant."

Gallery: 'Tragic ex-hero' Schumacher should retire again - Hakkinen