It is likely to shoot from below the break or near ground level and may grow very quicly as there is a large root to shoot ratio. You have to decide whether you want to keep what in effect will be a scrub tree or replace it. If looks are not important then keep it.
I agree with alan, it may be worth giving it a chance to re-grow. I've seen many in gardens that have been lopped quite severly and resprouted and in time have formed a nice shaped tree.
Saw off any splintered branches and check the roots are still firm. Good Luck. Tbird+
Thank you both for your comments. I'm not a complete novice but I needed some reassurance as I hate to kill anything unnecessarily. I suppose it will give the tree more character!