Further back, Airwaves Yamaha, at this point, were having a difficult race, with Camier still outside the top ten and Ellison, struggling with illness, making steady progress from tenth having suffered a bad start.
By contrast, Brookes was making headway through the field having started a lowly 17th. Up to sixth by lap nine when he overtook Laverty, the Australian was soon up to fourth when he passed Harris having already seen Easton forced into retirement with a suspected oil leak.
With a substantial gap to make up on the leaders still, Brookes' cause was aided by the fact Andrews was slipping back into the clutches of Walker, who in turn was pulling Hill along too, the trio separated by no more than half a second as they stalked each other around the tight circuit.
Walker eventually made his move to reclaim the lead on lap 18 with a smart dive down the inside at the hairpin. However, a tardy exit out of the final corner gave Andrews and Hill a run at him down to the opening bend, the pair sweeping through and demoting Walker back to third.
By this point, they had been joined by Brookes, who was now the fastest man on the circuit and looking like a genuine threat to snatch victory with only a handful of laps remaining.
However, Walker was proving difficult for Brookes to dispatch of, the HM Plant Honda adopting unusual lines in his attempts to find a way through.
Nonetheless, Brookes lined up Walker for a pass at the tight hairpin, but was seemingly struggling to stop the bike before the bend, the Australian being catapulted from the machine and being flung directly into Andrews, two positions further up the road.
Bringing down Andrews, who was on course for a maiden BSB victory despite carrying a painful scaphoid injury, the confusion forced Hill and Walker directly behind to lay down their bikes too in avoidance of the carnage going on around them. When Harris and Laverty were forced to do the same thing, the red flag was immediately shown.
While it is yet to be determined if human or mechanical error was the cause of the accident, the incident, unsurprisingly, riled a number of team bosses in the pit lane, for whom it denied some breakthrough results.
Confusion subsequently followed with the results, with race director Stuart Higgs declaring that the classification comes as a result of a 'snap-shot' taken at the time of the red flag. It declares that any rider not upright is not