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Opinion of Third person or Expert opinion

The term ‘opinion’ means something more than mere relating of gossip or of hearsay. It means judgment or belief, that is a belief or conviction resulting from what one thinks on a particular question. What a person thinks in respect to the existence or non-existence of a fact is opinion, and whatever is presented to the senses of a witness and of which he receives direct knowledge without any process of thinking and reasoning is not opinion. As a general rule, the opinions of a third person’s are irrelevant in evidence law. They form a part of “res inter alias acta” which means any act done between two persons does not harm or benefit others.

But, there are cases in which the court is not in a position to form a correct opinion (e.g. when the question involved is beyond the range of common experience or common knowledge), without the help of persons who have acquired special skill or experience in a particular subject. In these cases, the rule is relaxed, and expert evidence is admitted to enable the court to come to a proper decision. The rule admitting ‘expert evidence* is, thus, founded on necessity. Thus, Sections 45 to 51 deal with the cases when the opinions of third parties become relevant.

Opinion of Experts

Section 45 & 46 of the Indian Evidence Act, 1872 speaks about, “Opinions of experts” & “Facts bearing upon opinion of experts”. Section 45 permits only the opinions of an expert to be cited in evidence.

Who is an expert?

An expert witness is a person who has skill, knowledge, devoted time and has undergone training in a field he deems to be an expert. An expert witness is one who has devoted time and study to a special branch of learning, and thus is specially skilled on those points on which he is asked to state his opinion. “Ramesh Chandra Agarwal v. Regency Hospital Ltd.1)”. An expert is not a witness of fact but the evidence provided by him has an advisory character. It is the duty of the expert witness, to provide necessary information and scientific criteria to enable the judge to form his own independent opinion. An experienced police officer may be permitted to give ‘expert’ evidence as to how an accident may have occurred.

An expert opinion will not be read into evidence unless he is examined before the court and is subjected to cross-examination. It is upon the Court to determine whether the skills and knowledge amounts to an expert’s opinion. Both plaintiff and respondent have the privilege to bring in an expert to assert and supplement evidence.

The opinion provided by the expert will be considered admissible evidence after the Court has scrutinized the method employed and opinion generates conviction. If the expert cannot be present due to extenuating circumstances, his opinion can be taken in a way of affidavit, written questionnaire, telephonic conversation or even video conferencing.

However, in practice, the value of an expert opinion is not more than the value of the eye witness account. In case the eye witness account is inconsistent with that of the expert opinion, direct evidence (i.e. eye witness account) is to be given priority. In case the eye witness account is totally contradictory to that of the expert opinion then the credibility of the eye witness account is to be seen. If the eye witness account is believed to be credible then the eye witness account is to be taken and conviction can be done on its basis even though expert evidence is going against it.

Therefore, the expert opinion is just an opinion and the court can form its own opinion even if it is totally contradictory of the expert’s opinion. So, the courts have to give due regard to the expert’s opinion but they are not bound by it.

Prem Sagar Manocha v. NCT of Delhi, 2016 SC 290

In case the question was arised that can an expert be tried for perjury? This question was discussed in this case. This case was in relation to the ballistic expert in the Jessica Lal murder case.

In this case, the defence said that there was another man in the crime scene other than the accused who fired and due to which Jessica Lal was killed.

The ballistic expert said that two bullets have been fired by two different guns. But he also said that he is not saying anything conclusively and all this is just his opinion. Later when the accused was convicted and it was proved that the accused was the one who fired the gun the ballistic expert was convicted of perjury. On appeal to the Supreme Court, the Apex Court quashed the order for perjury saying that an expert is not a witness we only take his opinion.

Police personnel who are having certificates of technical knowledge and also are having long experiences of inspection examination and testing of arms and ammunition must be held to experts in firearms examination.

Areas wherein an expert opinion is required

Foreign law

Law which is not implemented or applicable in India is considered foreign law. Law which is not in force in India is foreign law. A judge is required to interpret and apply all the laws of the land however it is not expected from a judge to be an expert in foreign law as well. There is no necessity to call in an expert as foreign law can also be proved under Section 38 by production of a book printed by the authorities. Foreign law is considered a question of fact. In the question of Hindu Law and Mohamedan Law, the opinion of the expert would be irrelevant as the onus to interpret and rightfully implement the laws is upon the Court.

Science & Arts

The terms Science and Arts are broadly constructed to inculcate various fields under this category. These terms include all subjects pertaining to Science or Art. These terms are not limited by the narrow understanding of ‘science’ and ‘arts’.


The opinion of a medical officer and reports are generally considered as evidence. The opinion of the doctor who conducted the initial post mortem or inspected the injuries of the victim supersede the opinion of the subsequent doctor who formulates opinion based on X-ray reports, post mortem reports and other medical tests. However, if the essential tests are not preformed and opinion is formulated on limited grounds, the opinion of the medical officer will not be relied upon. Test such as DNA test which are highly conclusive in nature are relied upon unless mishandling or corruption of the report is proved. In certain cases, wherein the question of legitimacy of child is in question, DNA test are directed as a routine procedure, but reasons for the same are to be recorded.

Shah Nawaz v. State of U.P. (2011) 13 SCC 751

Ascertaining age – It has been held that evidence for ascertaining age ignoring the date of birth given in the mark sheets and school certificates will not hold good. Medical evidence as to determining the age is to be taken only in cases where prescribed method of ascertaining the age are not available.

Amol Chauhan v. Jyoti Chauhan, AIR 2012 MP 61

Medical examination of potency – medical evidence can be taken in cases relating to the potency of the spouse. In this case, the wife filed a divorce petition on the grounds of impotency of the husband, the court ordered for a medical examination of the husband’s potency.

Aruna & Anr. v. Mukund & Ors., Crl. Appeal No. 2063/2010, SC

Judgment delivered in October 2019. In case of Medical Negligence - the Supreme Court reiterated that examination of a report of an independent medical expert is crucial before proceeding against a doctor accused of medical negligence. Earlier, the Apex Court had in “Jacob Mathew v. State of Punjab & Anr2)”., laid down guidelines governing the prosecution of doctors for the offence of criminal negligence, punishable under Section 304A of IPC.

In the present case, the Appellants Aruna along with another had impugned the order passed by the Nagpur bench of the Bombay High Court, whereby the order of the Sessions Court, discharging them from the charges of Section 304A read with Section 34 IPC was quashed. It was their case that the impugned order had been passed without taking into account the above directions issued by the Supreme Court.

Considerably, the Trial Court had framed charges after examining the witnesses. However, revision of the said order was allowed by the Sessions Court which went on to discharge the Appellants. This order of discharge was subsequently questioned before the high court, which set aside the order of discharge and restored the order of the Magistrate.

Noting that the courts below had not proceeded in conformity with the above said Supreme Court ruling and had not obtained any expert opinion, the bench of Justices Arun Mishra, Vineet Saran and S. Ravindra Bhat said,

As admittedly, no medical expert has been examined in this case, we set aside the impugned orders passed by the courts below and remand the case to the trial court to examine the witnesses and to take the view of the medical expert on behalf of the complainant and only thereafter, to form an opinion whether any charge is made out in the case or not.“


The opinion of a handwriting expert is admissible under Section 45 of the act, however it is not binding. The evidence of handwriting cannot be considered a conclusive proof. Thus, conclusion cannot be solely derived from it. The opinion of a handwriting expert requires further corroboration to be considered reliable either direct or through circumstantial evidence. The Supreme Court gave guidelines for proof of documents; by direct evidence, by expert’s evidence and finally by court through the method of comparison. The opinion of handwriting experts is also applicable in criminal cases.

State of Maharashtra v. Sukhdev Singh, 1992 SCR (3) 480

In this case the court has laid down the principles of judging opinion of handwriting expert, namely;

  1. The identification done through handwriting does not share the same merit as identification done through finger prints. In comparison more weight is given to finger prints as opposed to handwriting.
  2. Corroboration is required as handwriting is evidence is a weak form of evidence and cannot be relied upon solely.
  3. The genuineness of the specimen handwriting as that of the suspect must be established.
  4. Expert’s competence, reliability and ability needs to be established before the Court.
  5. The reason for the expert’s findings and opinion should be based on a scientific principle and should be convincing in nature.
  6. The Court should be caution in basing its judgment on the opinion of the expert.

Padum Kumar v. State of U.P., Crl. Appeal 87/2020, SC

The Supreme Court reiterated that without independent and reliable corroboration, the opinion of the handwriting experts cannot be relied upon to base the conviction. The bench of Justice R. Banumathi and Justice AS Bopanna before acting upon the opinion of the hand-writing expert, prudence requires that the court must see that such evidence is corroborated by other evidence either direct or circumstantial evidence.

The contention taken in this appeal was that, without proving that the accused has forged the signature in delivery slip, the conviction of the appellant under Sections 467 and 468 IPC cannot be sustained.

On this Supreme Court observed, 'Of course, it is not safe to base the conviction solely on the evidence of the hand-writing expert. As held by the Supreme Court in “Magan Bihari Lal v. State of Punjab 3)” that “expert opinion must always be received with great caution…… is unsafe to base a conviction solely on expert opinion without substantial corroboration. This rule has been universally acted upon and it has almost become a rule of law.” It is fairly well settled that before acting upon the opinion of the hand-writing expert, prudence requires that the court must see that such evidence is corroborated by other evidence either direct or circumstantial evidence.

However, in this case, the Court noted that the courts below have not based the conviction solely upon the opinion of the hand-writing experts. The bench said, the evidence of hand-writing experts is only a corroborative piece of evidence to corroborate the evidence of other prosecution witnesses.


Examination of finger prints as opposed to handwriting is a matter of science. Since finger prints cannot be changed nor can there be several opinions pertaining to the same. Such evidence can be admissible in Court without corroboration. Furthermore, finger prints are unique and no man can have same finger prints.

Foot prints

Foot impression does not have same evidentiary value as finger prints. The science of foot impression is archaic and rudimentary. Thus, it cannot be considered reliable with proper corroboration.


The ballistic reports are used to establish that a particular bullet came from a specific firearm. The science of ballistics is helpful to determine the distance, severity and the type of weapon that was used to commit a crime. The report of ballistics is often considered essential in cases where firearms are used. The report is admissible without calling the expert to appear as a witness. If report is provided without examining the wound or the firearm but done through examining the pictures, such a report was considered unreliable. Therefore, the firearms or ballistic expert must formulate his opinion through his own findings and observation.

Drugs & Narcotics

Narcotics expert witnesses may become relevant for numerous types of cases, as narcotics may pertain to litigation for a variety of reasons. Narcotics expert consulting may provide valuable information for cases involving such areas as law enforcement procedures, crime scene investigation, pain management, security management, computer forensic investigation, drug enforcement, police practices and training, pharmacology, pharmaceuticals, financial crimes, and other issues concerning the use of narcotics, as each may be at the center of a narcotics-related lawsuit.

Electronic Evidence

As per Section 79-A of the Information Technology Act, 2000 (21 of 2000), in the matter of examination of electronic evidence, the opinion of the examiner is a relevant fact. And, also in Section 45-A Indian Evidence Act, but Section 45-A will come into play only when the electronic evidence is produced duly complying with the terms of Section 65-B.

Other kind of experts

Motor vehicles inspector, evaluation of property, tracker dog, psychological autopsies, ear print comparison, palm impressions, chemical analyzer, nautical assessors among others.

Evidentiary value of Experts

The Evidence Act only provides about the relevancy of expert opinion but gives no guidance as to its value. The opinion of an expert should be supported by the facts and circumstances of the cases, contradiction due to other evidence or fallacies in the findings of the expert render the evidence inadmissible and unreliable. An expert’s opinion is not binding upon the court. Further the opinion of an expert cannot supersede evidence of an attesting witness.

The value of expert opinion suffers from various drawbacks'. There is the danger of error or deliberate falsehood. “These privileged persons might be half blind, incompetent or even corrupt.” It would be highly unsafe to convict a person on the sole testimony of an expert. Therefore, a conviction cannot be based solely on the opinion of an expert without substantial corroboration.

Conflicts of opinions of experts lead to the discretion of the Court in forming its decision looking into the signatures on such documents. An expert can only formulate an opinion if all the required material is provided to him, if his opinion is based on incomplete documents, it cannot be relied upon. The opinion of the expert should be limited to the content referred to him, anything beyond that would not be admissible in the Court.

S. Gopal Reddy v. State of A.P, AIR 1996 SC 2184

In this case the court observed that expert evidence are just a mere opinion and not the substantive or a probative evidence; according to the procedural rule the opinion or the inference of the expert is not safe as they don’t have any independent value so they must be corroborated with the circumstantial evidence.

Opinion as to Handwriting when Relevant

Section 47 of the Indian Evidence Act, 1872 speaks about, “Opinion as to handwriting when relevant”. Section 47 of the Indian evidence act says that when the court has to ascertain whether a certain document is written or signed by a particular person or not then the opinions of persons, who are acquainted with the handwriting of that person, as to whether the document in question is written or signed by that person or not will be relevant.

According to this section the a person is said to be acquainted with the handwriting of another person if he has seen that person write or he has received documents from that person or when in the regular course of business he receives the documents that are supposed to be written by that person have been habitually submitted to him.

For example: - If we suppose ‘A’ is the secretary of ‘B’, the owner of a firm and thus ‘A’ has to submit to ‘B’ a written report written by ‘A’ himself about the daily business carried out by the firm. When the case before the court is if a document is written by ‘A’ or not then the opinion of ‘B’ is relevant in that matter since ‘B’ used to be acquainted with the writings of ‘A’ in the daily course of business.

Modes of Proving Handwriting

The Evidence Act recognize the following modes of proving handwriting:

  1. By the evidence of the writer himself.
  2. By the opinion of an expert (Section 45).
  3. By the evidence of a person who is acquainted with the handwriting of the person in question (Section 47).
  4. By the court itself comparing the handwriting (Section 73).

Opinion as to Digital Signature when Relevant

Section 47-A of the Indian Evidence Act, 1872 speaks about, “Opinion as to digital signature when relevant”. Section 47-A says that when the question before the court is about the authenticity of electronic evidence of any person then the opinion of the certifying authority who issued the electronic certificate will be relevant.

Opinion as to Existence of Right or Custom

Section 48 of the Indian Evidence Act, 1872 speaks about, “Opinion as to existence of right or custom when relevant”. Section 48 says that when the court has to see whether a general custom or right exits or not then the court can take the opinions of people who are likely to know about the existence of such customs or rights. For the purpose of this section general custom means a custom that is applicable to a considerable class of people.

In case of a custom which is related to one family only then the senior member of the family is to be questioned to look for the authenticity of such customs and if it is a custom followed by the entire community then the senior member of the community is to questioned.

Section 48 of the Act, widens the scope of experts. Thus, historians can be referred to, in cases where the relevant fact is pertaining to customs and rituals.

Opinion as to Usages, Tenets, etc.

Section 49 of the Indian Evidence Act, 1872 speaks about, “Opinion as to usages, tenants, etc. when relevant”. Section 49 speaks about the opinions about the usage tenets etc. when relevant. It says that when the Court has to form an opinion as to

  1. The usages and tenets of any body of men or family, or
  2. The constitution and government of any religious or charitable foundation, or
  3. The meaning of words or terms used in particular districts or by particular classes of people,

then the opinions of persons having special means of knowledge thereon are relevant facts.

Opinion on Relationship

Section 50 of the Indian Evidence Act, 1872 speaks about, “Opinion on relationship when relevant”. This section says that whenever the court has to form an opinion as to the relation between two persons then the opinion of any other person who is having the special means of knowledge regarding that by being a member of the family or by any other means is a relevant fact. However, it is provided that such opinion will not be sufficient in proving a marriage under the Indian Divorce Act, 1869 and also in prosecution under Sections 494, 495, 497 or 498 the Indian Penal Code, 1860.

Bant Singh v. Niranjan Singh, (2008) 4 SCC 75

This case is related to the knowledge about property as family member– When there was a property dispute in a family and the plaintiff contended that the defendant’s mother was actually his sister then an 80 years old witness was produced who was the brother-in-law of the defendant’s mother. He had all the knowledge about family affairs and also attended the marriage of the defendant’s mother. He was supposed to have a special means of knowledge.

Grounds of Opinion when Relevant

Section 51 of the Indian Evidence Act, 1872 speaks about, “Ground of opinion when relevant”. It says that whenever opinion a living person becomes relevant then the grounds on which his opinion is based also becomes relevant. The opinion of an expert by itself may be relevant, but would carry little weight with a court unless supported by a clear statement of what he noticed and upon what he based his opinion.

For example: - If an expert is giving his opinion on something then all those experiments performed by him because of which he reached that opinion also becomes relevant.

About the Author

  • Adv. Abhishek Gupta (Natraj Legal Solutions)
  • Delhi High Court
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AIR 2010 SC 806
2005 6 SCC 1
1977 2 SCC 210

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