You planted the bulb upside down in a pot that was too small. There wasn't enough room in the pot for the roots to effect their geotropism. Whew!! Now to answer that, I have either recovered from my New Years hangover or I am still under the influence:)

Crumpet, the drainage in that pot might be compromised, and the roots are avoiding the saturated compost in the bottom.
Loosestrife, "geotropism" isn't a word that I would use while under a hangover! :)

thanks , both, but I am puzzled that the other 2 bulbs in that pot are growing normally - now about 2 - 3 inches high. The weird one has just a healthy looking tip showing.
The pot is ceramic ,about 10 inches deep and has grown normal hyacinths in previous years....

Later=
Just looked up Geotropism which
might well be the answer as they are in a mix of new bulb compost and last years unused rose compost so maybe I left some uncrumbled solid chunks which have remained dry.

Thankyou

Well done L'strife, as long as you don't still have a headache its probably a good feeling, lol......