Note that the presence of the letter H in a two-letter code indicates a highbridge double-decker. Where a lowbridge equivalent type existed, they were numbered in a common series. The only highbridge vehicles bought new were the Ailsas.
Note also that the first six Leyland Leopards, originally T1-T6, were re-classified TS1-TS6 to indicate that they were short, L2 models (rather than the longer PSU3s). The first 53-seat Leopard / Alexander AYS was therefore T7.
Code  | Type  | First example  | 
A  | 1962  | |
AC  | 1966  | |
AH  | Ailsa (highbridge)  | 1978  | 
B  | Bristol Lodekka (short)  | 1955  | 
BE  | Bristol Lodekka (extended)  | 1963  | 
BL  | Bristol Lodekka (long)  | 1965  | 
BN  | 1966  | |
C  | 1955  | |
Tiger/Dorchester/B10M coaches   | 1984  | |
CS  | 1973  | |
D  | Daimler Fleetline CRG6LX  | 1971  | 
Dennis Dominator  | 1978  | |
DD  | Dennis Dorchester  | 1983  | 
FS  | Ford A0609  | 1978  | 
H  | Guy Arab double-deck  | 1943  | 
HL  | Leyland Titan (highbridge)  | 1961  | 
HR  | 1961  | |
K  | Guy Arab single-deck  | 1948  | 
L  | 1929  | |
LC  | 1985  | |
LO  | 1986  | |
LT  | 1982  | |
N  | 1979  | |
R  | Dodge S56  | 1986  | 
SP  | Seddon Pennine   | 1985  | 
T  | 1961  | |
TS  | 1961  | 
The next list shows all type codes used since introduction of the scheme in 1932.
Code  | Type  | First example  | 
A  | 1932  | |
1962  | ||
AC  | 1966  | |
AH  | Ailsa (highbridge)  | 1978  | 
B  | 1932  | |
1938  | ||
Bristol Lodekka (short)  | 1955  | |
BE  | Bristol Lodekka (extended)  | 1963  | 
BL  | Bristol Lodekka (long)  | 1965  | 
BN  | 1966  | |
C  | 1932  | |
1936  | ||
1955  | ||
Tiger/Dorchester/B10M coaches   | 1984  | |
CS  | 1973  | |
D  | Daimler CF6 and CG6  | 1932  | 
Daimler   | 1943  | |
Daimler Fleetline CRG6LX  | 1971  | |
Dennis Dominator  | 1978  | |
DA  | Daimler CF6 (with   | 1934  | 
E  | 1932  | |
1942  | ||
DD  | Dennis Dorchester  | 1983  | 
F  | 1932  | |
FS  | Ford A0609  | 1978  | 
G  | Leyland Tiger TS7T (3-axle)  | 1935  | 
H  | Guy Arab double-deck  | 1943  | 
HH  | Guy Arab double-deck (highbridge)  | 1961  | 
HL  | Leyland Titan (highbridge)  | 1961  | 
HR  | 1961  | |
K  | Guy Arab single-deck  | 1948  | 
L  | 1929  | |
LC  | 1985  | |
LO  | 1986  | |
LT  | 1982  | |
M  | 1930  | |
N  | 1979  | |
P  | Daimler CP6  | 1932  | 
R  | 1936  | |
Dodge S56  | 1986  | |
SP  | Seddon Pennine   | 1985  | 
T  | 1932  | |
1961  | ||
TS  | 1961  | |
V  | 1932  | |
W  | 1932  | |
Y  | Dennis Lancet  | 1936  |