For most, the weekend is a time for rest and relaxation.

Surgeon Obi Nnajiuba, however, spends his weekends caring for trauma patients while super-fast cars or motorbikes race past at high speed.

The fifth-year registrar in upper-gastrointestinal surgery at Barking, Havering and Redbridge University Hospitals NHS Trust (BHRUT) is a medical volunteer at Brands Hatch, a motor racing circuit in Kent.

Obi got involved around a decade ago when he noticed the Brands Hatch logo on the uniform of colleagues at Kent Air Ambulance.

As a “casual observer” of motorsport, Obi’s involvement was driven by his medical interest in traumatic injury and pre-hospital care.

“That’s always something I have been interested in,” he said.

Despite the high speeds, Obi said he would “rather crash a race car at 100mph than crash my family car at 60mph on the A13”.

“They are built differently," he explained.

“You do see people walk out of absolute wreckages, thinking ‘blimey, how did you survive that?'”

He has, however, seen two fatalities in his time: a motorcyclist who suffered head and chest injuries after coming off her bike and a marshal who died when a car flew off the circuit and hit their post.

The job can be hazardous for the medics too.

Even when races are yellow-flagged for an accident – meaning cars slow down and are not allowed to overtake – flying debris can pose a risk.

“We are always told: 'Never turn your back to the action',' said Obi.

“I have had colleagues sat in the medical car and cars have come past and a spring or something has come off and smashed through the medical car’s window.”

Obi grew up in Rainham and Newham and volunteered at Oldchurch and St George’s hospitals as a teen, before eventually working as a senior house officer at BHRUT from 2013 to 2015.

He returned to the trust last October, after a period working at Southend and Royal London hospitals.

As well as Brands Hatch, Obi occasionally works at Silverstone and Goodwood circuits. While he has become more interested in motorsports over time, he maintained that he is still not “a petrolhead”.