Jenson Button's exit in the first part of Formula 1 qualifying for the British Grand Prix was the result of a loose rear wing that prevented him from running again.
The McLaren driver watched on from the pits as he was bumped out of contention for a spot in Q2, having had his only run in the session compromised when his rear wing detached from the floor halfway round his flying lap.
"The rear wing came detached from the floor coming out of Turn 8 [Woodcote]," Button said.
"It just slowly deteriorated from there with the rear of the car - we lost a lot of downforce.
"All the way through the high-speed corners I was telling the guys there was a lot of oversteer.
"I'm surprised I did the time I did. We tried to fix it to go out again but we ran out of time.
"We missed doing a run with the car in the shape it should have been."
Button almost got a reprieve when it appeared Kevin Magnussen could lose his place in Q2 as a result of a track limits infringement.
But after the McLaren driver ran back to the pits a decision was not made on Magnussen's lap in time to allow him to compete in the next stage of qualifying.
"We weren't confused, we were just waiting for information," said Button.
"Supposedly Kevin drove off the circuit - I haven't seen it.
"We thought he'd get his lap taken away.
"It's a shame they couldn't do something before Q2 because as soon as Q2 starts it's game over.
"We were very unlucky to be 17th, and unlucky they didn't make a decision on Kevin before the end of Q1.
"That's frustrating but the main issue for us was the rear wing wobbling around all over the place."
Team-mate Fernando Alonso, who will start ninth after making it through to Q3, said Button's failure was another worrying sign of reliability problems for McLaren following 'engine data issues' that cost the Briton running on Friday.
"I've been hurt by reliability issues in the last two races and now Jenson yesterday and today in qualifying," said Alonso.
"So yeah, we have a problem - we need to keep working not only on performance but the reliability side.
"We need to make sure everything is good for tomorrow. We are more or less in the top 10 this weekend, so why not in the race?
"We are in the middle of the fight and able to compete with the people around us.
"We still need speed on the straight but here we can compensate with the long corners at Silverstone.
"We just need to make sure reliability is OK."