Umpire

An umpire in cricket is a person who has the authority to make decisions on the cricket field, according to the Laws of Cricket. Besides making decisions about legality of delivery, appeals for wickets and general conduct of the game in legal manner, the umpire also keeps a record of the deliveries and announces the completion of an over.
A cricket umpire is not to be confused with the referee who usually presides over only international matches and makes no decisions affecting the outcome of the game.

Cricket matches have two umpires on the field, one standing at the end where the bowler delivers the ball (Bowlers end), and one directly opposite the facing batsman (usually, but not always, at square leg). However, in the modern game, there may be more than two umpires; for example Test Matches have four: two on-field umpires, a third umpire who has access to video replays, and a fourth umpire who looks after the match balls, takes out the drinks for the on-field umpires, and also arranges travel and meals for all of the umpires.

When a ball is being bowled, one umpire (the bowlers end umpire) stands behind the stumps at the non-strikers end (that is, the end from which the ball is being bowled), which gives him a view straight down the pitch.

The second (the strikers end umpire) takes the position that he feels gives him the best view of the play. Through long tradition, this is usually square leg - in line with the stumps and a few yards to the batsmans leg side - hence he is sometimes known as the square leg umpire.

However, if a fielder takes up position at square leg or somewhere so as to block his view, or if there is an injured batsman with a runner, then the umpire must move somewhere else - typically either a short distance or to point on the opposite side of the batsman. If the square-leg umpire elects to stand at point, he is required to inform both the batsmen, the captain of the fielding team, and his colleague. He may also move to the point position later in the afternoon if the setting sun prevents a clear view of the popping crease at his end.

It is up to the umpires to keep out of the way of both the ball and the players. In particular, if the ball is hit and the players attempt a run, then the umpire behind the stumps will generally retreat to the side, in case the fielding side attempts a run out at that end.
At the end of each over, the two umpires will exchange roles. Because the bowlers end alternates between overs, this means they only move a short distance.

For certain decisions during a match, the on-field umpire may refer to the Third Umpire if there is one appointed, who has access to television replays. The Third Umpire is most often used in the case of run-outs, where the action is too fast for the naked eye but can be also used to decide the cases of disputed boundaries and catches, when the umpires cannot decide if the ball has struck the ground before being caught (but not to decide whether or not the ball in fact struck the bat or gloves of a batsman). Third Umpire referrals for LBW dismissals have also been trialled in the 2002 ICC Champions Trophy is Sri Lanka, and in the 2007 English Domestic Pro40 competition, and are currently being trialled in international matches