The Wicket-Keeper shall remain wholly behind the wicket until a
ball delivered by the Bowler touches the bat or person of the
Striker, or passes the wicket, or until the Striker attempts a
run. In the event of the Wicket-Keeper contravening this Law,
the Umpire at the Striker's end shall call and signal "no ball"
at the instant of delivery or as soon as possible thereafter.
