If it has broken at the release lever end, in the footwell, you may be able to find enough of the inner cable to clamp it in a pair of mole grips and release the bonnet catch. You might have to remove the glove box and side trim first, so you can see more clearly and get sufficient access. If at the bonnet end, it may need more thought and investigation as you go along, but I would start by stripping out the nearside wheel arch liner and possible removing the front bumper to see what it revealed, and what access you can find. I used to have to do similar quite often at work when we recovered cloned cars that were locked and I had to examine them. I never had to do that with a V40 though. If it's not a fairly simple break at the footwell end, you might be better consulting a Volvo deale first, as they must have come across this before and may know exactly how to deal with it.