my iveco daily 35s11 wont turn over?

i stopped to put fuel in at a petrol station, when i got back in the van would not turn over, the starter motor seems to make a click when i try to start but thats all it does?, it was fine when i left the house the battery is fine too i checked this first, it starts straight away with a bump but not from the key, any one have any ideas? if the starter motor was on way out i would have noticed it playing up wouldnt i?