British (and other) Weapon Nomencalture

Attention Eurolisterdudes!

What's the L in L7? (the NAC AR)

Americans use M- for rifles (Military?). The Canadians use C- 
(Canadian?). Germans use G (Gewehr?). Russians have a series of AKs 
(Avtomat Kalashnikova - or something like that). But what does the L 
in L7 stand for? Why do the Brits use L designations for rifles? 

And what designation do Brits use for pistols? (Yanks use M-... which 
again I think is Military). I don't even recall what Canucks use (I 
only ever recall that we called the Browning Hi-Power a "Browning", 
don't ever recall but I'm sure it had a code). And I think the 
Germans use P- (Pistol?). 

If I'm correct, the french might use:
FA - Fusil D'Assaut
FTE - Fusile Traleur d'Elite (sp?)
( dunno what they'd use for a pistol )