Charles Leclerc drove for two laps of the Spanish Grand Prix without his seatbelt fastened.
The Ferrari driver's car had stopped on track right before the entrance to the pit-lane with an engine issue caused by an electrical fault. After initially preparing to climb out of the car, Leclerc resumed the race in 20th when his car restarted.
A full video of what followed that was published on F1.com has revealed the radio messages which followed between the driver and Ferrari.
As he went down the start-finish straight, Leclerc informed Ferrari he intended to 'box' -- the word for making a pit-stop -- although he did not mention why: "Oh, no no no, there is something strange. I will box this lap."
His engineer, referring to the team's data about Leclerc's faulty engine, replied: "For us, everything is fine, everything is fine."
Bizarrely, Leclerc kept his radio button pressed down for most of that lap, prompting his engineer to ask him to switch it off a couple of times.
One lap after his spin, having passed the pit-lane entry a second time, Leclerc radioed Ferrari to inform them his seatbelt was off.
"Guys, we need to box, we need to box," he said as he drove down to Turn 1. "When I went for the button to switch the car on again, my seatbelts are off now.
"When I brake I am moving quite a bit. I don't mind but I'm pretty sure nobody will be happy with me driving without seatbelts."
Ferrari then told him to pit at the end of that lap to rectify the issue, saying "box now and we will try to fix it".
On the lap to the pits, Leclerc's engineer again asks: "Let me know if you need help with seat belts. We'll try to fix it."
A flustered-sounding Leclerc replied: "For sure I need help. It's like if I was going on the car. In the car."
Leclerc told them they needed a new attachment for the belt but the team did not have one ready when he returned to the pit-lane, at which point the decision was made to switch off the engine retire the car.
Explaining what happened immediately after the race, Leclerc said: "I tried to start the engine after the issue and it was not starting. So I took off the seat belt getting ready to get out. But then they asked me to try one last time and actually the last time it actually worked again. So then I had no seat belts, so I had to stop."