Another operation has been carried out on Formula One champion Michael Schumacher and his condition is improving slightly, the director general of the hospital where he is being cared for said today.

The intervention took place overnight and a new scan carried out this morning shows slight improvement, Jacqueline Hubert told a news conference.

The champion driver has been in an induced coma following surgery after he suffered a severe head injury while skiing off-piste in the resort of Meribel in France on Sunday.

He is believed to have been saved by his skiing helmet, which split on impact.

Doctors have refused to speculate on a prognosis for the 44-year-old German.

Ms Hubert said: "Very late in the evening a new brain scan was carried out and we could see that there was a slight improvement of the situation.

"The scan allowed us to suggest to the family that we had a new surgical intervention to reduce the haematoma , and that surgical intervention took place overnight.

"A new scan was taken this morning and it showed a slight improvement, a slight radiological improvement."

The seven-times champion was admitted to Grenoble Hospital in France suffering from intracranial haematoma - blood clots - bruising and swelling of the brain.

Since his first surgery he has been kept in a state of hypothermia by controlling his temperature to keep it at 34C-35C (93.2F-95F).

He was reportedly travelling at speeds of up to 60mph when the accident happened. He had gone with his family to Meribel in the French Alps for the festive season.

His 14-year-old son was reported to have been with him at the time of the accident..

Rescuers were on hand within minutes and he was initially conscious after the fall before deteriorating into a critical condition.

Professor Jean Francois Payen, head of anaesthetics, said: "At the end of the afternoon yesterday we had a transitory improvement of intracranial pressure.

"Michael Schumacher's intracranial pressure improved and we were able to carry out a scan without taking any kind of unnecessary risk.

"And that particular scan showed a few signs that were relatively stable, and I'd like to underline that. In other words, we had no sign that implied that there was a worsening of the initial lesions.

"And at the same time, talking in a collegial fashion with our colleagues, with our neurosurgeons, at that moment we felt that it was possible, taking into consideration that his state had slightly improved, we suggested that we should carry out a surgical intervention that had not been envisaged at the beginning."

Professor Emmanuel Gay, one of the specialists treating Schumacher, said: "The dangers are still there. We cannot say that we have won because there are still some highs and some lows, but it's better than yesterday.

"He is still in a very critical condition, this has not changed. And we still cannot tell how he will be, which state he will be in when he does wake up.

"We cannot speculate on the future because once again it would be too early to do so."

Doctors confirmed that the two-hour surgery was carried out to remove the largest of a series of blood clots in the racing driver's brain.

"There are still many haematomas in the brain, with little bits everywhere," Professor Gay said.

"That is what makes the situation critical and it needs to be looked at hour by hour, day by day.

"The situation can still evolve, but we won't be able to evacuate the other haematomas at the moment because they are not accessible. They are not as big as the one we removed yesterday."

Schumacher has received an outpouring of support from the racing world, with former and current stars urging him to pull through.

German chancellor Angela Merkel said she was "extremely shocked along with millions of Germans" to learn of the accident.

Schumacher retired from F1 for the final time in 2012 after a three-season comeback with Mercedes.

Schumacher, who also raced for Jordan, Benetton and Ferrari, won the last of his world titles in 2004.

He won two with Benetton in 1994 and 1995 before moving to Ferrari and winning five in a row from 2000. The German has 91 career wins.