Second place aboard their Audi R8 LMS GT3 in the second of the two races at the British venue on Sunday was more than enough to give Vanthoor and Weerts the crown with two rounds left to run at Valencia next month.
The Belgian duo moved up to the runner-up spot on the final lap of the race behind the Toksport Mercedes-AMG GT3 of Maro Engel and Luca Stolz when their nearest rivals for the championship lost victory for the second time of the day.
Raffaele Marciello and Timur Boguslavskiy, who were second in the points heading into Brands, dominated the race only for a wheel problem to strike their Auto Sport Promotion Merc.
Boguslavskiy had been able to hold off the challenge of Stolz over the second half of the one-hour race before a problem at the right front corner slowed the car.
The Russian lost the lead at Hawthorns and then went off the track at Stirlings before crossing the line in sixth place as the front right wheel minus its tyre parted company with the car.
The ASP pair had earlier lost victory in the opening race of the day when Marciello was deemed to have caused the accident in which Ollie Wilkinson’s Jota McLaren ended up vaulting the barriers at Dingle Dell.
The Italian was given 40s time penalty, which dropped the car to 17th position.
Victory for Marciello and Boguslavskiy in race two wouldn’t have been enough to keep the championship battle open going into the series finale at Valencia.
#88 AKKA ASP Mercedes-AMG GT3: Timur Boguslavskiy, Raffaele Marciello
Photo by: SRO
Weerts said: “That was quite an eventful race: it was about taking zero risks and securing a podium.
“Mathematically we have put it out of reach, so this is a good opportunity to thank everyone at WRT.”
Engel had trailed pole-winner Marciello through the first half of the race, which included a brief safety-car period.
The German was nearly five seconds behind the ASP Merc when he stopped as soon as the pit window opened after 25 minutes.
Stolz was able to close down Boguslavskiy after the pitstops were complete and was right with the ASP car for the final 20 minutes.
Vanthoor held a watching brief in third position throughout the opening half hour, while Weerts moved in on the leaders as the Mercs battled over the closing laps.
Stolz crossed the line 1.9s ahead of Weerts after Boguslavskiy slowed.
The second of the ASP Mercs, shared by Jules Gounon and Petru Umbrarescu, inherited the final place on the podium, finished 13s down on the WRT Audi.
Toksport also won the Silver Cup division with fourth place overall for Oscar Tunjo and Juuso Puhakka.
They took class honours by just four tenths from the WRT Audi of Frank Bird and Ryuichiro Tomita.
Miguel Ramos and Henrique Chaves won the Pro-Am class on the home track of the Barwell Lamborghini team.