Could be a weak or loose connection, check the battery connections first. Get battery posts clean and shiny with sandpaper, also the same for the cable connections that sit on the posts. You also want to make sure they're tight.

The 12 volt battery is starting to have a shorted out cell. Prove this to yourself by having the battery *load tested at ant store other than Auto Zone where new batteries are sold. A quick 15 second load test will tell you the reserve amperage capacity. Amperage spins starter motors not voltage.

later

Yes could well be a loose connection somewhere by the sound of it but could be an almost unlimited number of other things too

This morning i went to start my car and it just ticked over and didnt start until the 3rd attempt, then i drove 15 miles, parked up and went back around 40 minutes later and i went to start it again and NOTHING, didnt tick over and didnt do anything when the key was turned not even my electricals in my car come on, After 9/10 attempts it started again. What could be the problem ??? ive heard it could be a dodgy wire but im a bit worried.