McLaren confirms cause of early Alonso F1 test crash

McLaren has confirmed that a loose wheel nut caused Fernando Alonso to spin off just 30 minutes into Formula 1's winter testing schedule in Barcelona, causing a red flag.

McLaren unveiled its new Renault-powered F1 car, the MCL33, ahead of the 2018 season last week before completing a successful shakedown at Navarra in Spain that left Alonso promising "good times" for the team's fans this year after a difficult period working with Honda.

However, Alonso brought out the first red flag of winter testing when he spun into the gravel at the final corner in the opening hour of testing, with a wheel coming free from his McLaren car.

Speaking to reporters ahead of the lunch break in Barcelona, McLaren executive director Zak Brown confirmed a loose wheel nut had caused Alonso's off.

"We had a wheel nut issue. We'll get back out here this afternoon," Brown said.

"I know Eric [Boullier, McLaren racing director] will be doing a debrief later today with all of today's activities, so I'll leave him to tell you about today.

"It's what testing is for. I think all teams will have a variety of issues throughout testing. That's exactly what it's for.

"We're going to lose very little time. It's no big deal at all."

Alonso completed six laps before the issue occurred, completing a fastest time 1:24.202.