This happened to me last weekend, a couple of kilometres from home! The leather around one of the buckles snapped (yeah..i think I've only oiled it once, its cheap indian stuff to so that wouldnt help)
I was like um..hmm....what to do...
Tried to fix it but I couldnt. I can make a bridle/halter out of rope but of course I didnt have any!
So I clipped the reins onto his noseband and rode him back home like that, he was pretty good about it actually!
Anyways, my invention:
So yeah, just thought id share the photos