Non breaking small space

[Nigel King]

In LaTeX there is \, which is a small space which does not break easily at
the end of lines. It can be used as the space between say 10 and GHz.
Obviously I could use units but that seems to be a bit of a sledgehammer to
crack my nut. ConTeXt has |~| a small space but it breaks between lines. Is
there any solution that I have missed.
-- 
Nigel