Doctors treating Michael Schumacher for brain injuries say his condition has slightly improved following surgery last night.

But they stress that the Formula One legend is not out of danger and that the hours to come will be crucial.

Medics in the eastern French city of Grenoble say that a surprising improvement by late Monday created an opportunity for the operation to treat the effects of internal bleeding within his skull.

“This build up of blood was successfully drained and the figures for intra-cranial pressure markedly improved,” neurosurgeon Professor Emmanuel Gay told a news conference. “But, once again, the scan also shows that there are other lesions on the brain and these lesions must be monitored.”

There has been an outpouring of concern from fans since the retired ex-world champion fell and hit his head on a rock while skiing in the Alps on Sunday.

French authorities have opened an investigation into the accident, which took place off piste as Schumacher was out with his teenage son.

The 44-year-old German was wearing a helmet – a decisive factor in his survival – but he remains in a medically induced coma, fighting for his life.