A batter is run out if, at any time while the ball is in play, no part of their bat or person is grounded behind the popping crease and their wicket is fairly broken by the action of a fielder.
It is a legitimate mode of dismissal, and the International Cricket Council (ICC) playing conditions match the MCC Laws in this respect.
[4] The most notable example of this method of dismissal involved the Indian bowler Vinoo Mankad who ran out Bill Brown on 13 December 1947 in the second test during India's tour of Australia at Sydney.
[10][11] In July 2014, when England's Jos Buttler was run out by Sri Lanka's Sachithra Senanayake, the World Cricket Council, an independent consultative body of former international captains and umpires, unanimously expressed support of Sri Lanka's actions.
They may intentionally leave the crease not attempting a run, for example to talk to the non-striker or to pat the pitch.
But if an appeal is made, the umpire must give the batter out unless they consider that a dead ball pertained.
There have been instances, such as a Test match in 2006, when Muttiah Muralitharan left his crease to congratulate Kumar Sangakkara on completing his century, and was run out by Brendon McCullum.
[19] In a contrasting incident in a Test match against India in 2011, Ian Bell was initially given run out after leaving his crease, wrongly assuming his shot had reached the boundary, but the appeal was later withdrawn by the fielding captain MS Dhoni and Bell was allowed to resume his innings.