The clutch hose is a rubber hose that connects the top of the gearbox to the clutch slave cylinder and is used to transport hydraulic fluid in the clutch system. The rubber material is used to allow for engine movement but is prone to splitting so some people prefer to replace this with a steel wire hose which is coated in a plastic covering. This can provide a more solid feel to the clutch. The clutch hose is attached to the gearbox and clutch slave cylinder by a banjo bolt.

Failure of the clutch hose may first be noticed by a softer, spongier clutch or a hydraulic fluid leak in the driverside foot well. You may also notice occasional difficulty in changing gears and eventually this will become chronic if the clutch hose is not replaced. The clutch pedal may also be near to the floor making it impossible to operate the clutch. Failure of the clutch hose can cause failure of the clutch slave cylinder. 

Should your clutch hose become worn it should be replaced immediately to stop further damage to the clutch and gearbox system.