My Opel Astra 2008 won' start. Was perfectly fine earlier on today. Key turns in ignition all lights come on, boot then pops open! and I can hear a clicking sound from engine. Key fob working fine in locking car. Any advice

IG, March 2016

The rapid clicking sound you hear is the starter relay operating then dropping out then operating and dropping out again.

The battery has enough energy to operate low current devices - like the boot and the starter relay but as soon as the starter tries to draw 50+Amps to turn the engine over its voltages drops to a very low level - not enough to hold the starter relay which disconnects the starter motor - and suddenly there's enough voltage to operate the relay again - click-click-clickety-click.

Not enough energy in the battery to turn the engine over - either charge the battery of get a new one.

Good Luck..., March 2016