Walk, walking

A batsman who walks without waiting for the umpire's decision is, in effect, giving himself out. Walking is still regarded as the epitome of fair play in many cricketing circles but seems to be much less common in the professional game these days compared to former times. A notable exception is Australia's Adam Gilchrist who is known for walking when he believes he is out.
Umpires, however, should not just accept a batsman's decision at face value. At most it can be regarded as an acknowledgement that the ball came into contact with the bat - just one of the criteria for the striker to be out Caught. Players have sometimes been known to walk when, in fact, they were not out. Umpires have a duty to recall any batsman who is leaving the wicket under the misapprehension that he is out.