It provoked an enormous crash on the first lap that left two drivers hospitalised, blocked the circuit and caused the race to be restarted.
After a action-packed race it was the championship leaders that came out on top with Fabrizio Giovanardi winning from Jason Plato.
The crash was triggered by Mat Jackson who spun on the outside of Paddock Hill on the first corner and was collected by Matt Neal. Neal was then hit very hard by Dave Pinkney’s Alfa Romeo.
The ensuing carnage claimed Tom Ferrier, Eoin Murray, Martyn Bell and many others, and blocked the track completely. Neal and Pinkney were taken to hospital for checks.
Once the piles of wrecked cars were cleared away 15 were able to take the restart. Colin Turkington kept his lead from pole but Jason Plato dropped back behind Darren Turner and the Vauxhall pair of Tom Chilton and Fabrizio Giovanardi.
Turner was immediately all over Turkington for the lead, and Chilton clipped Turner on the third lap as the Seat driver tried to get alongside Turkington.
On lap five Turner got alongside the leader on the outside of Paddock Hill bend but slithered off and fell down to fifth behind team mate Plato.
Giovanardi was impatiently trying to find a way past team mate Chilton and nerfed him wide at Clearways. Plato followed Giovanardi through but Chilton reversed the move at Druids.
On the next lap Chilton made a mistake and fell back to sixth. Then leader Turkington pirouetted through 360 degrees at Paddock allowing Giovanardi through into the lead, followed by championship rival Plato.
That left Turner third, fending off Tom Onslow-Cole, Chilton and Turkington. Adam Jones, who had passed Gavin Smith on lap two, now took Mike Jordan for eighth. On lap 17 he dived past Gordon Sheddon in a brusque move at Graham Hill bend, but when Jordan tried to pass Sheddon as well the two made heavy contact, damaging both cars and putting the second Honda Civic out.
Onslow-Cole began to fall back, losing fourth to Chilton and fifth to team mate Turkington. On the final lap Chilton launched an attack on turner but slithered off at Paddock Hill, letting both the BMWs past.
Giovanardi had stretched a healthy lead over Plato by the end of the race who was followed home by Turner, Turkington and Onslow-Cole, then Chilton. In a repeat of his strong performances in the wet at Donington, Jones took seventh ahead of series returnee Gavin Smith.
Ninth was Matt Allison and Erkut Kilirmark took the final point, with Chris Stockton passing Richard Marsh for 11th at the line.