Cycle helmets probably protect riders from some life-threatening head injuries, doctors at London’s busiest major trauma unit have found.

In a ground-breaking study, they analysed the medical records of 93 cyclists treated over three years in the trauma and intensive care units and emergency department at St Mary’s hospital, Paddington.

They counted injuries such as skull fracture, brain haemorrhage and bruising of the brain in the 50 riders known not to have worn a helmet and the 19 who did.

Cyclists not wearing a helmet were almost twice as likely to fracture their skull – 62 per cent compared to 32 per cent of those with this injury.

No cyclist wearing a helmet suffered an epidural haemorrhage – bleeding between the outer membrane of the brain and the skull – and only one suffered a subdural haemorrhage, a similar type of bleed.

There was no difference between helmet and non-helmet wearers in the number of cyclists who suffered contusion, or bruising of the brain – showing the limited ability of cycle helmets to protect the brain from severe shaking.

The cycling community is split between those who wear helmets for safety and others who believe they are of little benefit and create the illusion among motorists that cyclists are less at risk of injury on the roads.

Mark Wilson, a consultant neurosurgeon at St Mary’s and one of the report’s authors, said the sample was too small to draw firm scientific conclusions from its findings.

But he said he hoped it would illustrate the benefits that helmets can provide in reducing the incidence of some types of head injuries.

He told me: “This is a tiny study. We really can’t draw any conclusions from it at all, but there is no way of doing a study where people are [deliberately] injured. What we did was to do the best we can from our data.

“The reason for doing this study was because I think there is a mixed message [about helmets] – that helmets are bad for you in some ways, or that people drive closer to you if you wear one.

“On an individual level, helmets make sense. If I said to you, ‘I’m going to head-butt you, would you like to wear a helmet or not?’ You would want to wear a helmet. We know that is common sense.”

Cycle helmet presentation

The researchers hope to update and expand the study by including data from other major trauma centres, including the Royal London.

The study, which looked at patients admitted to St Mary’s between January 2011 and December 2013, found that the largest proportion of cycling injuries were caused by collisions with cars (41 per cent) and falls (38 per cent).

A total of 25 per cent of cyclists were found to have been drinking alcohol, leading the researchers to declare this a “risk factor” in injuries.

Mr Wilson, who also volunteers on London’s Air Ambulance, said: “People, rather than drive, will get on their bike. A significant number then fall off, or hit the kerb and fall off. Alcohol and cycling is a big deal, just as alcohol and walking down the stairs is a big deal.”

Download a summary of the research here: Cycle helmet presentation