Class
1 = All two wheel drive cars up to 1450cc.    
2 = All two wheel drive cars with capacities between 1451cc to 1650cc, with 8 valves or less.    
3 = All two wheel drive cars with capacities between 1451cc to 1650cc, with more than 8 valves.    
4 = All two wheel drive cars with capacities between 1651cc - 2050cc, with 8 valves or less.    
5 = Historic Category 1, 2, 3 & 4 & FIA Appendix K cars as defined in the General Regulations of Motorsport UK.    
6 = All front wheel drive cars with capacities between 1651cc - 2050cc, with more than 8 valves.    
7 = All rear wheel drive cars with capacities between 1651cc - 2050cc, with more than 8 valves.    
8 = All two wheel drive cars with capacities 2051cc and over.    
9 = Any other four wheel drive cars not classified in Class 10 or 11, without a sequential gearbox.    
10 = FIA Homologated GpA four wheel drive, Super 2000 & R4 cars, and any cars previously homologated as such, providing these run as per their FIA homologation papers. All Metro 6R4’s and any derivative therefrom. Any other four wheel drive car not classified in class 11, with a sequential gearbox.    
11 = FIA Homologated WRC cars and cars previously homologated as such, and FIA Homologated R5 cars. Any derivative therefrom.    

Class
BRC1 = See Supplementary Regulations Article 6 for definition.    
BRC PRODUCTION = See Supplementary Regulations Article 6 for definition.    
JBRC = See Supplementary Regulations Article 6 for definition.    
BRC3 = See Supplementary Regulations Article 6 for definition.    
BRC4 = See Supplementary Regulations Article 6 for definition.    
NRC1 = All two wheel drive non-homologated cars up to 1450cc.    
NRC2 = All two wheel drive non-homologated cars - 1451cc to 1650cc.    
NRC3 = Front wheel drive non-homologated cars - 1651cc to 2050cc.    
NRC4 = Rear wheel drive non-homologated cars - 1651cc to 2050cc.    
NRC5 = All two wheel drive non-homologated cars over 2051cc.    
NRC6 = Any four wheel drive car not classified in Class NRC7.    
NRC7 = Any derivative of FIA R5 car converted to RHD.