Hill was drawn on pole for the reverse grid final race, with former champions Matt Neal (Civic Type R) and Jason Plato (Vauxhall Astra) behind him on the grid.
While Hill made a strong start, he was soon under immense pressure from Neal, with the triple champion squeezing past on the main straight on the first lap. Hill tried to fight back exiting Old Hall but tagged the back of the Civic, pitching Neal into a wild spin through a cloud of tyre smoke.
Neal somehow emerged unscathed, albeit well down the order, but several cars were damaged in the ensuring mayhem, including Plato’s Astra, which dropped a line of oil down before the hairpin.
Hill was left in a clear lead, but Butcher and Jelley closed in on him near the end. Butcher looked at a move in the hairpin, but hit the oil and slithered wide, allowing Jelley through for second.
Jelley would move up again following the race, inheriting the win when stewards handed Hill a 20-second penalty for the clash with Neal. Oliphant picked up second ahead of Tordoff and Jordan.
Turkington followed up his two wins with a solid ninth place, extending his championship lead over team-mate Jordan.
The next BTCC event is at Snetterton in Norfolk on August 3/4.