A starter motor is energised from a starter relay - a big solenoid switch usually on top of the starter motor.
The coil of your starter relay might be a short circuit causing the fuse to blow. The wire that runs to the starter solenoid switch might be shorting out somewhere there could be a wiring fault inside or close to the ignition / starter switch.
You might try this to get the engine started - switch on the ignition and run a starter jump lead - just one - from battery +ve to the terminal of the big cable that runs to the starter. Do not leave it connected. In the event that the engine fires up then remove the cable immediately.
I have little confidence that this trick will work but you never know
Good Luck...
September 2015