Vauxhall Astra wont start

[trailertam]

I have fully charged the battery and when I try to start the car there is only a click. If i turn the headlights on, they shine bright,and when i try to start the car, they fade to nothing.
I can jump start the Astra from another car but the Astra engine turns over slowly as if the battery in the Astra is flat. What can be wrong in that the car will not start on its own but will start when jump started.
Thanks

[AlBags]

The battery has a failed cell. Replace it.
You can seemingly charge it up .. but there will be no power to crank engine over for more than a few seconds.
If you want second opinion .. Go to an Auto-Electricians to get a new battery .. When you get there, ask them to do a discharge test on the battery first. Going by what you have stated, it will fail.
Al.

[MantaRay]

As AlBags indicates, it's probably a duff battery. They can fail without any apparent warning. Might be worth cleaning the battery terminals though, and see if it's still the same.

[trailertam]

Having charged up and used two different batteries prior to asking my question, I was a bit sceptical of the two anwsers posted. One of the batteries I had used was a little suspect but both had shown as being fully charged on the charger. How could two batteries fail at the same time !!! I was sure the fault was somewhere else but the thought of checking with yet another battery seemed a little easier that crawling under the car to get at the starter motor and solenoid so I pinched the battery from my tractor and guess what.........the car started first time. Thanks both for your help
Trailertam

[AlBags]

Good to be of service. No charge either : )