Tim+ writes:

I was going to suggest, just buy another, but a look online
suggests that the type with the riveted or welded on thin
stainless blade seems to have disappeared. This is a shame as the
blade is thinner and more flexible than on the newer
ones.

You can get them from Nisbets.co.uk, for prices ranging from
cheap to ridiculous. Ours is one of the ridiculous price ones,
but Im sure it was much cheaper when we bought it (hence some
reluctance to just replacing it).

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2014-04-05)