Section 142 of Evidence Act "When they must not be asked"
Leading questions must not, if objected to by the adverse party be asked in an examination-in-chief, or in a re-examination, except with the permission of the Court.
The Court shall permit leading questions as to matters which are introductory or undisputed, or which have, in its opinion, been already sufficiently proved.
Section 143 of Evidence Act "When they may be asked"
Leading questions may be asked in cross- examination.
Section 144 of Evidence Act "Evidence as to
matters in writing"
Any witness may be asked, whilst under examination whether
any contract, grant or other disposition of property, as to
which he is giving evidence, was not contained in a
document, and if he says that it was, or if he is about to
make any statement as to the contents of any document,
which, in the opinion of the Court, ought to be produced,
the adverse party may object to such evidence being given
until such document is produced, or until facts have been
proved which entitle the party who called the witness to
give secondary evidence of it.
Explanation - A witness may give oral evidence of statements
made by other persons about the contents of documents if
such statements are in themselves relevant facts.
Illustration
The question is, whether A assaulted B.
C deposes that he heard A say to D-"B wrote a letter
accusing me of theft, and I will be revenged on him". This
statement is relevant, as showing A's motive for the
assault, and evidence may be given of it, though no other
evidence is given about the letter.