Jupp took the lead with two laps to go and managed to hold off a last lap effort from Harvey to take the win by seven hundredths with Vaughan third and Nelson and Kellett completing the top five.
Charlie Barlow scored one of the best results of his career with a sixth place finish while Patrick Walsh drove from 30th on the grid to take 12th. Italian driver Andrea Russo made a fine British debut with 16th place although O Plate winner Lando Norris retired after moving from 29th on the grid into the top ten inside ten laps.
Kartmasters history was made in Mini Max as reigning British Cadet Champion George Russell became the first driver ever to win three GP plates in a row in different classes. The 2008 WTP and 2009 Cadet Comer GP plate winner added the Mini Max crown to his list of achievements despite a fraught start to the 20-lap final.
From pole position Russell took to the grass on the run to the first corner and lost nearly ten places in the ensuing melee, which eliminated potential winners Oliver Myers, Ryan Morgan and Lemuel Pay and held up many more.
However as Harry Webb led from Adam Mackay and Ashley England Russell clawed his way back to the front, finally taking the lead with two laps to go. After slowing the pace down at the front Russell waited until the chasing trio fell over themselves before sprinting clear on the last lap to take the win by a little over two seconds.
Webb slipped to fourth on the last lap but then inherited third at the line with Mackay and England collided, England being eliminated and Mackay excluded. Adam Glear snuck through the wreckage to grab third place with Josh White and George Line rounding out the top five.
Further back there were standout performances from Jordan Baines (33rd to 10th) Jay Goodwin (31st to 11th) while Chinese driver Guan Yu Zhou took a highly creditable 14th, two places ahead of Russian driver Nikita Sidorov.
The Junior Rotax final was dominated by Sean Babington, who won by more than seven seconds after second place combatants Andy King and defending GP Plate champion Ash Hand tore chunks out of each other in the closing laps and lost a great deal of time.
King initially took second but was demoted a place after the officials judged his late race defending to be a little too harsh. Behind King, George Williams and an embattled James Singleton completed the top five while Jack Barlow's bid for victory, which had already been delayed by a spectacular roll at the start of the first final, ended when a chain came off.
Current Super One points leader Matt Parry was also in contention until a collision dropped him back to 13th while Dubai based driver Shahaan Engineer also finished down the field after an off track excursion.