Why not?! That sounds amazing, and by potting it up, you have nothing to lose . . . it would be worth finding out if it is hardy though (usually plants are kept frost free until they have good, strong roots).

The green growth at the top is a bit of a nuisance - what you need to do is encourage roots. The way to do that is to insert the cane (I'm assuming its a fairly hard, rigid stem) into some moistened, good quality seed and cutting compost such as John Innes No. 1, then keep it in reasonably warm temperatures until shoots start growing. The trouble is, you've already got shoots, which means you won't know when its formed roots, so strip most of the leaves off, just leaving one or two at the top. There's also more chance of success if the cane is dry when pushed into the soil, so take it out of the water and leave it somewhere coolish and airy (but not cold) to dry out for three or four days or more, however long it takes, before inserting into compost. You may find the leaves left shrivel and fall of, but that doesn't matter, what's important is getting the cane to produce roots.

More info here http://www.gardeningknowhow.com/ornamental/foliage/yucca/propagation-of-yucca-plant.htm
but its aimed at Americans living in dry, warm landscapes - you'll note the best time to attempt this is in spring, but you have no choice about when to do it, so you'll have to try it now.

Thank you for those answers, I shall take the plant out of the jar of water and dry it as advised. Hopefully it will survive if I get things right, I only bought it last minute as a spur of the moment thing to use up my small Euro change before flying home, really surprised when I ended up with some nice green leaves. i shall try to keep you posted as to the results.

Good luck Shoreside . . . it will be so satisfying if you manage to help your yucca to grow :)