Any whirring and clicking from the window regulator mechanism? If so it could be the window lift mechanism that's given up the ghost. When mine went I took the door card off and wedged the window in the up position to get me home:
1. Remove 2 screws securing hand rail to door.
2. Remove screw securing door handle escutcheon to door.
3. Remove escutcheon.
4. Remove 4 screws securing pocket to door.
5. Carefully release 10 clips securing trim casing to door.
6. If fitted, disconnect multiplug from upper door speaker.
7. Disconnect multiplug from lower door speaker.
8. Remove trim casing from door.
Ease the plastic membrane away from door (go carefully and you can stick it back down later) and you can get your hand in to lift the window up. If totally jammed you might need to undo the 2 small (8 or 10mm?) bolts that hold the bottom of the window to the lift track.
Long term fix is to replace the knackered regulator mechanism although I did read you could weld the broken part