Should be possible to to a tempory repair by the roadside.
Most common breakage is that the lead pulling out of one of the crimp-on ends. If this is the case, just open up the end and remake. The lead is normally a carbon conductive core (black strands) surrounded by insulation. If necessary, srip the insulation further back to leave about 10mm of carbon sticking out which then folds back over the insulation and goes into the crimp.
If the wire has broken in the middle, get a short length of metal wire, staple, paperclip etc. and push half length into the centre core each side to bridge then wrap round with tape to stop it pulling apart. Keep the join away from wiring or metal as it will not be well insulated.
Alternatively, as above, a motor factor is likle to have ignition cable he can crimp your ends onto.