I guess 'Huge' doesn't work for you then.
As a quick guess calculation i'd say around 650L (90cm front to back, 60cm floor to boot lid, and 120cm wide). It's probably on the low side, but i'm nowhere near it to measure and see.
If you are near yours then it's (height (in cm) * width (in cm) * depth (in cm)) / 1000 to get the litre capacity.