Help needed please...

I just bought a landrover discovery 300 tdi..it's my second one because I love them...
drove it home today and parked it up for about an hour, went back to go out and it will not start, not the battery all lights come on at first key turn, but when key is fully turned to start it is just dead....

Any ideas?...
Thank you

Pop over to new members section,and introduce yourself,Then pop over to the discovery section,someone on there will be glad to help you.