If by "bonnet" you mean the Hood then your hood release cable may broken and needs replaced. You will have to try and locate the end that located under the hood and then release it from there. Be aware you may have to remove the grill to get at it.
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if by ' hood' you mean bonnet, then I am having the same problem - I can't even find the release lever!
If by "hood" you mean bonnet if its the mk3 if you put your hand up behind your bonnet behind the ford badge you can feel the catch that keeps it shut. On the top of that you should be able to feel where the bonnet catches on, just pull the catch over and it should pop up, Might be a bit difficult by hand but you should be able to do it.