BHarrison replied:

Quickly check that no floor mats etc bunched under the pedal youll be suprised

if not then clutch is not disengaging fully

Bleed system for airlock (water vapor) may as well give it some fresh fluid while your there

check back of Master for a slow leak stick your head under the dash ,and dont forget a torch
or remove boot from slave and check for leaks

These are the cheap simple options

if none of the above

expensive /lotsa swearing and barked knuckles options

strip down clutch

worn/bent fork or fingers on pressure plate
sticky spigot

new clutch plates

try the simple ones first

cheers

Mickl replied:

First thing to do here is check you gearbox oil level. Next check the action of the hydraulics (get someone to push the pedal while you take a look and see that the slave cylinder moves the clutch fork ok) Has the fluid level dropped (even a little?) Has the pedal "feel" changed? even the smallest of leaks will let air into the system. Also check clutch pedal free play, make sure it's within specs.
Have you done any dusty trips lately? dirt building up on the input shaft and holding up the clutch has caused me drama's before.

howesy replied:

All of the above. And while you are checking the clutch fork take a look inside and check the pivot to see that the mushroom head of the pivot ball is still there they have been known to snap. Also were you in water, check the fluid in box and transfer case for contamination and if you refill it go for a lighter grade of gearbox oil such as an 80 grade. Gear changes are a lot smoother with the lighter oil.