Last year’s Walter Hayes Trophy winner Niall Murray is out of the 2017 event after contact with Sebastian Melrose forced both to retire from the first semi-final.
As Murray attempted to move up to second place he was forced onto the kerbs at Brooklands. His Van Diemen was launched into a spin as a result, leaving the Irishman stranded in the middle of the road.
Melrose, who had made good progress from 18th on the grid, then hit Murray’s car having been unsighted in the melee.
The race was red-flagged to clear up the wreckage, and was eventually won by Josh Fisher upon the seven-lap restarted encounter.
Both drivers were largely unhurt. Murray exited his car unaided, although Melrose had to be assisted to the ambulance and complained of knee pain.
Melrose said: “I made up a few places at the start and was catching people in front of me, I definitely felt I had the pace.
“Niall spun at Brooklands and I just didn’t see him. I was preparing my next move and didn’t have any time to react.
“My knee is in agony and down my right leg is sore, but I’m alright.”
Murray’s retirement put pay to any hopes of him repeating his 2016 triumph, having earlier been involved in a late-race collision in heat four.