Wrenches (spanners in the UK)

[livo@saglac.qc.ca]

I am told by a British friend that I must have  AS. spanners ( wrenches) 
In Canada however, their are two systems:
   metric and SAE.
 I assume that the US is the same. 
Questions:
Is SAE the same as AS?

If not, what does one use for Triumph Heralds and Spitfires in Canada and in
the US?

John V