If evidence is relevant the Court is not concerned with the method by which it was obtained. In Barindra Kumar Ghose & Ors. v. Emperor, ILR (1910) 37 Cal. 467 Sir Lawrence Jenkins repelling the contention that the Court must exclude relevant evidence on the ground that it was obtained by illegal search or seizure, said at p. 500 of the Report:
“Mr. Das has attacked the searches and has urged that, even if there was jurisdiction to direct the issue of search warrants, as I hold there was, still the provisions of the Criminal Procedure Code have been completely disregarded. On the assumption he has contended that the evidence discovered by the searches is not admissible, but to this view I cannot accede. For without in any way countenancing disregard of the provisions prescribed by the Code, I hold that what would otherwise be relevant does not become irrelevant because it was discovered in the course of a search in which those provisions were disregarded”.
The question arose before the Judicial Committee of the Privy Council in the well-known case of Kuruma v. Reginam,  1 All ER 236. In dealing with the question Lord Goddard, CJ. delivering the judgment of the Privy Council said:
“The test to be applied both in civil and in criminal cases, in considering whether evidence is admissible, is whether it is relevant to the matters in issue. If it is, it is admissible and the Court is not concerned with how it was obtained.”
The learned CJ. further observed:
“In their Lordships’ opinion, when it is a question of the admission of evidence strictly it is not whether the method by which it was obtained is tortuous but excusable, but whether what has been obtained is relevant to the issue being tried.”
Again, the House of Lords in R.V. Sang,  2 All ER 1222 reiterated the same principle that if evidence was admissible it matters not, how it was obtained. Lord Diplock after considering various decisions on the point observed that however much the judge may dislike the way in which a particular piece of evidence was obtained before proceedings were commenced, if it is admissible evidence probative of the accused’s guilt ‘it is no part of his judicial function to exclude it for this reason’ and added:
“He has no discretion to refuse to admit relevant admissible evidence on the ground that it was obtained by improper or unfair means. The court is not concerned with how it was obtained.”
Exception to the rule
There is a long line of authority to support the opinion that the Court is not concerned with how evidence is obtained. The rule is however subject to an exception. The Judge has a discretion to exclude evidence procured after the commencement of the alleged offence, which although technically admissible appears to the Judge to be unfair. The classical example of such a case is where the prejudicial effect of such evidence would be out of proportion to its evidential value.
Coming nearer home Supreme Court in Magraj Patodia v.R.K. Birla & Ors.,  2 SCR 118 held that the fact that a document which was procured by improper or even illegal means could not bar its admissibility provided its relevance and genuineness were proved.
In R.M. Malkani v. State of Maharashtra,  2 SCR 417 the Court applying this principle allowed the tape-recorded conversation to be used as evidence in proof of a criminal charge.
In Pooran Mal etc. v. Director of Inspection (Investigation) of Income-Tax Mayur Bhavan, New Delhi & Ors.,  2 SCR 704 the Court held that the income-tax authorities can use as evidence any information gathered from the search and seizure of documents and accounts and articles seized.