I have a 1973 1.6 Aircooled vw bug.

This morning my clutch has suddenly gone spongey, the car still goes into gear fine, doesn't crunch and doesn't pop out of gear.

Does anyone have any idea what might be wrong?

Spongy Clutch could mean youve got air in your system.
Check your fluid level, cos if its below the level of the hose, that could be an easy way for air to enter it.

Id say top up your Brake fluid (should be linked to clutch cylinder) then bleed the clutch

Are the clutches cable operated??

it will be


if so it will be your adjuster slipped or the cable stretched

or your clutch pressure plate is going

Or maybe it's just 'moved' off the fixings or clutch release lever.