Is it a self adjusting cable? It should take up the slack automatically if so. To check its operating as it should, push down on the clutch release lever on the front of the box, the fat part of the cable should collapse, and expand when you let go. If this doesn't happen, you'll need a replacement cable, get a self adjusting one and you should have no trouble. They are really easy to fit - 15mins on the side of the road..

If its a manually adjusted cable, you need to see how much you can lift that same lever, half an inch or so maximum.
If it moves more than this, slacken the lock nut on the end of the cable, and tighten the tensioning nut until the lever can only be lifted half an inch. then re-tighten the lock nut.

 

Must check which cable i have. Id say its a self adjusting as there is no lock nut on the end of the clutch cable. There is a stopper on the end and a slot locking clip to lock it in place. I only pressed the pedal once r twice. The car was layed up for years so it could be gone a bit stiff maybe. So the big black stump is were the slack is takin from? Might giv it a gander tomorrow. Cheers

 

Sounds like a self adjusting one.. If its seized, bin it and get a manual adj. one, less than €30 in the local autofactors here.