REPORTS that Richard Hammond was initially able to speak after his high-speed crash seem on the face of it to be positive, but every casualty officer is aware of the dangers of the patient who has had a head injury and immediately after the injury is talking, chatting and even joking with bystanders.

The accident may well have lowered the presenter’s blood pressure, but for whatever reason the bleeding in the skull had not begun in earnest. Once the bleeding occurs, the intra-cranial pressure rises and the patient loses consciousness.

If a clot forms and it can be evacuated, or if the bleeding point can be tied off within a reasonable time, all may be well. If not, the outlook would be worrying.

Staff at the Leeds General Infirmary, which has a specialist neurological unit, have been careful in their remarks, saying only that Mr Hammond’s “significant brain injury” gives them cause for concern but that they are “relatively optimistic” the presenter will make a good recovery.

The best hope is that there was no actual bleeding, but the brain was only so badly shaken that any swelling occurred from tissue fluid collecting in and around it.

The cautious casualty officer will always admit any patient who has had a head injury of this type so that if there is a change in the patient’s condition, he can immediately have the appropriate scans and brain surgery.

As in any head injury, the outcome will not be known for days or weeks.

Motoring accidents are a leading cause of brain damage, and other high-profile drivers have faced a long road to recovery after serious crashes.

In the case of Stirling Moss’s crash in 1962, it was many months before he regained consciousness. When he did, he found that although most of his faculties returned, his ability to remember emotional relationships had gone.

In hospital he was visited by a large number of charming and beautiful women who professed to be his girlfriends, but he was unable to remember just what the relationship had been and therefore how he should behave to them.

He went on to make an almost complete recovery, establishing a career outside racing and becoming a great advocate of road safety.