You need to do something in the engine bay, so you pull the release lever (or insert the key behind the badge in the grille on certain models) and instead of the usual clunk, there's the ominous sound of silence. You've got a stuck bonnet. Here's how to solve it.
1. Get some help
Ask an assistant to push down at the front of the bonnet (gently but firmly) while you pull on the release lever again. If the cable is jammed between the lever and the catch, this may free it and the bonnet will pop up as usual.
2. Pull the cable manually
Take a closer look at the release lever. You may be able to release the handle and the trim around it to reveal the cable that's attached to it. If the lever is part of the dashboard, take a look underneath - you should see the cable.
Carefully detach the end of the cable from the mechanism (take a photo of how it was secured to make sure you can put it back) and, using a pair of pliers, grip the end and pull the cable towards you to replicate the motion of the lever.
If the bonnet pops up, the cable is likely to have lost its tension and will need to be replaced. Have another look at the lever, though, because the mechanism may have broken.
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3. Work through the grille
On some cars you'll be able to unlatch the bonnet release catch by working a pair of long-reach pliers or similar through the grille.
Look for a hook that the release cable attaches to. Pull this hook with the pliers and the bonnet should open. Take care not to damage the grille as you do this.
4. Jack up the car
If you can't work through the grille, use a trolley jack and axle stands (with the car on solid, level ground, the handbrake on and chocks behind the rear wheels) to raise the front of the car. Do NOT use your car's emergency jack.
Now reach an arm up from behind the front bumper and release the bonnet lever/mechanism. You may be able to peer through the grille with a torch to see what you're doing but will probably need to look up from underneath for the best view.
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