I'm not sure how well the BBC researched this but, for what it's worth:
http://www.bbc.co.uk/dna/h2g2/A8245910
The one used by the Royal Air Force during WWII and which is used in war films especially those based in the era, was as follows:
A - Apple
J - Johnny (or Jug)
S - Sugar
B - Beer
K - King
T - Tommy
C - Charlie
L - Love
U - Uncle
D - Dog
M - Mother
V - Vic (or Victor)
E - Edward
N - Nuts
W - William
F - Freddy
O - Orange
X - X-Ray
G - George
P - Peter
Y - Yorker (sometimes Yoke)
H - Harry
Q - Queen
Z - Zebra
I - Ink (or Indigo)
R - Roger (or Robert)