Old Leafsprung Land Rovers

The six pot station wagon has a tendency to do this, I free it off as follows.

1) Jack up the rear of the vehicle and put it on chassis stands so the wheels are off the ground
2) Start the engine with it in 4th gear high ratio (i.e. rear wheel drive only!)
3) Accelerate to 40mph
4) Fully depress the clutch pedal then stamp on the footbrake. The clutch frees off. I've tried 20 and 30mph and it doesn't seem to be enough.

It's never failed for me, however I do have a field with lots of space to do it in. Perhaps not ideal if the vehicle lurching forwards would impact something or someone.