Question: In which year was this British racing car manufacturer founded that built a vehicle Australian Jack Brabham drove during the 18th BRDC International Trophy?

Context articles: 1950 BRDC International Trophy
Tom Belsø
Brabham
Brabham BT3
1960 BRDC International Trophy
1984 BRDC International Trophy
1966 BRDC International Trophy
Cooper T51
1971 BRDC International Trophy
1964 BRDC International Trophy

The 2nd BRDC International Trophy meeting – formally the Daily Express BRDC International Trophy – was held on 26 August 1950 at the Silverstone Circuit, England.
 The race was run to Formula One regulations, and was held over two heats of 15 laps each, followed by a final race of 35 laps.
 Italian driver Nino Farina emerged the winner, in an Alfa Romeo 158, repeating his victory from the 1950 British Grand Prix, held at the same circuit in May.
 He beat his Argentine team-mate Juan Manuel Fangio, and British driver Peter Whitehead in a Ferrari.
 Other notable entrants were the two BRM V16 cars entered for Raymond Sommer, Peter Walker, Raymond Mays and Reg Parnell.
 Unfortunately, their legendary lack of reliability resulted in neither car completing a lap in anger.
Tom Belsø (born 27 August 1942 in Copenhagen, Denmark) is a former motor racing driver.
 He is credited as the first Formula One driver from Denmark.
 He started out in touring cars but became a Formula Two racer in 1972, with his best result being a fourth place at the Albi Grand Prix, finishing 17th in the European F2 Championship.
 In 1973 he raced a Lola in Formula 5000.
 He also raced in a few non-championship Formula One races, finishing 7th in the 1973 Race of Champions and 8th in the 1973 BRDC International Trophy, and retiring in the 1974 BRDC International Trophy and 1975 Race of Champions.
 He contested the 1974 Rothmans 5000 European Championship winning at Snetterton and finishing 8th in the Series.
 He also competed in the 1977 Shellsport 5000/Libre series and finished fifth in a Radio Luxemburg-sponsored Lola T330-Chevrolet.
Motor Racing Developments Ltd., commonly known as Brabham , was a British racing car manufacturer and Formula One racing team.
 Founded in 1960 by two Australians, driver Jack Brabham and designer Ron Tauranac, the team won four Drivers' and two Constructors' World Championships in its 30-year Formula One history.
 Jack Brabham's 1966 Drivers' Championship remains the only such achievement using a car bearing the driver's own name.
The Brabham BT3 is a Formula One racing car.
 It was the first Formula One design to be produced by Motor Racing Developments for the Brabham Racing Organisation, and debuted at the 1962 German Grand Prix.
 The Brabham BT3 was the vehicle with which team owner – then two-time World Champion – Jack Brabham, became the first driver ever to score World Championship points in a car bearing his own name, at the 1962 United States Grand Prix.
 The following year Brabham also became the first driver ever to win a Formula One race at the wheel of an eponymous car, again driving the BT3, at the 1963 Solitude Grand Prix.
 The BT3 design was modified only slightly to form the Tasman Series-specification Brabham BT4 cars.
The 12th BRDC International Trophy was a motor race, run to Formula One rules, held on 14 May 1960 at the Silverstone Circuit, England.
 The race was run over 50 laps of the Silverstone Grand Prix circuit, and was won by British driver Innes Ireland in a Lotus 18.
 The race was particularly notable for the death of experienced American driver Harry Schell in a violent accident during practice in wet conditions.
The 1984 BRDC International Trophy (formally the XXXVI Marlboro / Daily Express International Trophy) was a Formula Two motor race held at Silverstone on 1 April 1984.
 It was the 36th running of the International Trophy, and the seventh and last under Formula Two regulations.
 It was also the opening race of the 1984 European Formula Two Championship.
The 18th BRDC International Trophy was a motor race, run to Formula One rules, held on 14 May 1966 at the Silverstone Circuit, England.
 The race was run over 35 laps of the Silverstone Grand Prix circuit, and was won by Australian Jack Brabham in the Brabham-Repco BT19.
 With no Race of Champions in 1966, the International Trophy formed the first major race of the European season, being run just a week before the start of the FIA World Championship in Monaco.
 The 1966 season was significant, as changes to the F1 formula had allowed an increase in engine capacity from 1.5L to 3L.
 This then was the first opportunity for many teams to test their new cars against top-line opposition.
The Cooper T51 was a Formula One and Formula Two racing car designed by Owen Maddock and built by the Cooper Car Company for the 1959 Formula One season.
 The T51 earned a significant place in motor racing history when Jack Brabham drove the car to become the first driver to win the championship with a rear-engined car, in 1959.
 The T51 was raced in several configurations by various entrants until 1963 and in all no less than 38 drivers were entered to drive T51s in Grand Prix races.
The 23rd BRDC International Trophy meeting - formally the GEN/Daily Express BRDC International Trophy - was held on 8 May 1971 at the Silverstone Circuit, England.
 The race was run to Formula One and Formula 5000 regulations, and was held over two heats of 26 laps each, the final results being an aggregate of the two.
 Graham Hill emerged the winner in the unique Brabham BT34 "lobster-claw" car, designed by Ron Tauranac.
 It would be the two-time World Champion's last victory in a Formula One race.
 The 1971 event was also notable as one of the few competitive outings for the Lotus 56 gas turbine car.
 However, suspension failure on only the third lap of the first heat resulted in early retirement for driver Emerson Fittipaldi, although the car held together for long enough to take third place in the second heat.
The 16th BRDC International Trophy was a motor race, run to Formula One rules, held on 2 May 1964 at the Silverstone Circuit, England.
 The race was run over 52 laps of the Silverstone Grand Prix circuit, and was won by Australian driver Jack Brabham in his own Brabham BT7.