Practical guidance on what conduct is consistent with the ‘rule in Browne v Dunn’ appears in Reid v Kerr (1974) 9 SASR 367.
Amongst other things, a ‘half hinted imputation’ is insufficient and the cross-examiner must put the proposition ‘fairly and squarely … so as to allow the witness to respond’.
See also http://realgy.wordpress.com/2012/02/08/the-rule-in-browne-v-dunn/