Dead on key

Hi
Could be a problem with your starter motor relay but sounds more like a immobiliser problem. I would reccomend checking to see if the immobiliser light goes out on the dash when you try to start the car. If the light stays on you will need a auto locksmith to re-programme the key

check the fuses in the fuse box under the bonnet cant remember which one but its 25 amps

There are various posts on this site about peugeots being "stuck" in Economy Mode and not starting. Well this happened to me today. I had been cleaning the 307 HDi for about an hour. All clean I desided to move the car closer to the garage the plug in the hoover. Key into the ignition and ........ nothing! dash warning lights lit up and the centre console screen had a warning of " Economy Mode activated" across it. Now, this has happened before to me so no panic. I turned the ignition key again (this normally cures the situation) - Nothing. I lock the car up, ignition key in again - nothing. I checked out the posts and concluded that a new battery was probably required. Having check out how to replace the battery in the trusty Haynes manual I was shocked by the complexity of such a simple job. To cut a very long story short I desided instead to call out the AA (cost £83.00). The guy spent 10 minutes and hey presto the car fires up! Gob smacked I asked him what he had done. Quote - he said - the car had entered the "economy mode because I had been cleaning it with the doors open and run the battery down. The car had then automatically gone into economy mode to protect itself but the Peugeots can be a pig to get back out of this mode sometimes. The trick is to run a thick wire from the battery positive terminal directly to the starter motor and force the car to turn over with the ignition turned on. This forces the car to start and come out of Economy Mode. He then advised to leave the car running for half hour or so to let the battery charge up and for everything to reset itself. He then also advised never to leave the car doors or radio on without also having the engine running.

So next time your Pug strops out and sulks in the Economy Mode the moral of the story is to kick the starter motor with a bit of 12v juice and stick two fingers up to the electronic brain.