Alex Albon suffered a scary fire in the pit lane during the first free practice session on Friday as Williams began preparations for Sunday's Singapore Grand Prix.

Williams team principal James Vowles has revealed the cause of the pit lane fire that brought Alex Albon's FP1 session at the Singapore Grand Prix to a premature end on Friday. The Thai-British driver's car required a complete rear-end replacement due to the incident.

Albon pulled into the pit lane just minutes into Friday's FP1 outing around the Marina Bay Street Circuit with the rear of his Williams machine spitting flames. When he stopped in the box outside the team garage, smoke started to billow out.

Williams' mechanics worked away at the fire for over three minutes using extinguishers. They attempted to wheel the car inside, but as smoke spewed into the garage, they abandoned that idea. All the while, Albon was spotted on the broadcast with his visor up and his hands over his eyes.

“Yeah, everything looked okay up until Turn 10 of that lap, where we boxed him," Vowles explained. "And then all of a sudden the rear brake temperatures ramped up to a level where you really don’t want them, which is plus 1,000 degrees Celsius.

“So it looks like part of the rear circuit. Probably around, hard to know exactly, but something in the rear circuit anyway, hardware-wise, basically clamped on a little bit of braking force, and even though he came in slowly, by that point, it was too late.”

Vowles was asked by Sky Sports F1 about the damage done to Albon's FW47 machine. He explained: “It’ll be basically a rear-end change. So, it just takes time to evaluate. But it’s far easier now we have pre-built rear ends, gearbox, rear suspension, etcetera. It’s much easier just pulling that off and replacing the whole assembly.”

Fortunately for Albon, Williams were able to get his car ready for FP2 on Friday. The 29-year-old punched in the 13th-fastest time of the day, just under eight-tenths of a second slower than team-mate Carlos Sainz.

The duo were much more closely-matched in Saturday's FP3 outing, as Albon's best lap time was only just over half a second slower than Max Verstappen's at the top of the leaderboard. Sainz was the sixth-fastest driver, 0.244 seconds behind the reigning world champion.

Williams arrived in Singapore with momentum on their side after Sainz scored the first podium of Vowles' team principal tenure in Baku last time out. According to Albon, the result was symbolic of the culture shift at Grove under his leadership.

“Truthfully, I would say the whole attitude this year has shifted,” he explained. “And I don’t feel like the podium has necessarily invigorated the team more, because I can tell you, at Grove, everyone is super, super motivated. The culture and the energy in it is addictive. And you don’t really feel like there’s much more that the podium gave more than, if anything, proving a point."