Why won't my ford mondeo start?

Why won't my Ford Mondeo start I can start it using easy Start or I can start it pushing it and it will start but it will not start using the key it's a 2 litre TDCi

Because its broken silly! Now if you want someone to come up with the right answer you need more detail like does the batt have 12.6 volts in it. Does it click or make a hard clunk. Are the batt connections corroded and a few more