Williams team principal James Vowles has opened up on the blue flag incident involving Carlos Sainz and Oscar Piastri during the Hungarian Grand Prix.
While accepting responsibility on behalf of the team, Vowles also pointed to the issues with the FIA's automated marshalling system.
Speaking on the latest edition of the Vowles Verdict, the Williams boss broke down the chaotic sequence that led to Sainz's collision with Piastri, clearing his driver of any deliberate wrongdoing.
Instead, Vowles attributed the incident to a breakdown in race control technology and a delayed reaction from Aston Martin driver Fernando Alonso.
"Budapest was also just a frustrating event," Vowles explained. "We ended up obviously racing towards the back of the grid but got caught up in an incident with the leader of the race, and that's on us, not on Carlos at that point in time.
"I'll take us through more of that detail. There's a whole sequence about it. We need to make sure that as FIA systems do fail and they will fail from time to time, we have a slightly better mechanism in place."
According to Vowles, the confusion stemmed from the collapse of the FIA's automated GPS blue flag system. Typically, this system triggers a driver warning when a leader is 1.6 seconds behind, locking into an official blue flag condition at 1.2 seconds.
In Hungary, the system encountered major issues. Marshals initially relied on traditional waved flags before switching to flashing blue light panels, which failed to indicate which specific driver was required to yield.
"Two problems took place in Budapest. That flag system simply wasn't working. In fact, at one point, we were just operating with marshals doing their best by waving blue flags. And it's a very difficult thing for a marshal to do. They don't know when the cars are coming by and trigger that.
"What then was resolved was trying to use the flashing blue lights, but without indicating which driver it is. So now if I focus particularly on Carlos and Fernando, who was the car behind, and Oscar. Fernando had a number of blue flashing lights all the way through and, in fact, remained in position in front of Oscar, and you have to do it in order. So Fernando should have conceded that position earlier.
"What happened is he didn't but took an opportunity to go up the inside of Carlos into Turn 1. So at that stage, Carlos then became the car behind. And when you do, you have a number of marshal posts to therefore give up position. However, on the run down to Turn 2, Carlos was back ahead now. So the car behind is Fernando again with the blue light boards.
"And again into the next corner, Fernando went up the inside of Carlos, which made Carlos the car behind. And you'll see that on the video. And as Carlos came back on to rejoin, that's when Oscar went up the inside. So what complicated it was that, without the automatic system, cars were staying in place for perhaps longer than they should have done."
The Williams chief added: "Secondly, you have to know which one is exactly the car behind at the right moment. Now what we did do is communicate to Carlos into Turn 1 that Oscar was coming.
"What we should have done, because ultimately we're still racing for a non-points-scoring position, is indicate to Carlos that that was happening at the point where he was alongside Fernando on the run down to Turn 2. So that's what I mean by our culpability.
"But I hope what you can see from this was that it wasn't an attempt to go and block Oscar or otherwise. Actually, in this circumstance, there was another car that was the car behind and that should have probably conceded before we did."
Sainz was handed a five-second penalty for the collision. He finished in 18th, and Piastri later retired due to a gearbox issue.
