At common law, the general rule was that hearsay was inadmissible in evidence despite the many exceptions to the rule which exist. The hearsay rule is classically defined as "an assertion other than one made by a person while giving oral evidence in the proceedings is inadmissible as evidence of any fact asserted".
 The major justifications for the exclusion of hearsay at common law are that such evidence is potentially dangerous as there is the possibility of fabrication by witness by the fact that such evidence is not given under oath and that it poses difficulty in assessing the weight and reliability of the statement as the truth of the evidence is unknown.  On the other hand, renowned academicians have expressed concerns that the consequences of hearsay rule can lead to cogent evidence being excluded.
Certain hearsay evidence are said to be "credible, probative, and reliable, can give a better-rounded picture of what happened, and can be better than no evidence at all".  Cross's view is that "evidence of indisputable reliability has been excluded under the hearsay rule" and this causes decision which "were grossly unjust".  Apart from this, Law Commission itself says that "some hearsay is the best evidence and … the rule operates irrationally to prevent its admission". 
As a result of this, the exclusionary principle under the common law was applied until the Criminal Justice Act 2003 (CJA) was introduced to clarify and reform the law on the admissibility of hearsay evidence.  CJA expanded the limited number of exceptions under the common law, subjected the Act to further specified exceptions and a limited inclusionary discretion concentrating upon relevance and weight rather than admissibility. 
The basis of statutory admission of hearsay evidence under CJA is provided by s.114(1) and is limited to four categories of exception comprising: (a) statutory exceptions including those in the 2003 Act itself, (b) common law exceptions, but only to the extent preserved by s. 118, (c) hearsay admitted by agreement of all parties to the proceedings, and (d) the "safety valve".  These provisions will be examined in the following essay to determine if the rigidity of the hearsay rule under the common law has in fact been rectified. Preserved common law exceptions (i) Res Gestae
The phrase res gestae suggests that in order to illustrate and reinforce a fact, evidence of other facts and events may be adduced.  In Lord Tomlin's oft-quoted words, res gestae is a "phrase adopted to provide a respectable legal cloak for a variety of cases to which no formula of precision can be applied".  This becomes apparent when it is shown that res gestae exceptions are based on "weak theoretical assumptions about the inherent reliability of contemporaneous or spontaneous statements". 
In Ratten v R, Lord Wilberforce provided that statement may be admitted where it is "made in circumstances of spontaneity and involvement in the event that the possibility of concoction can be disregarded" and explained that the statement made must be "approximate but not exact contemporaneity". This application of Ratten has been described as "faintly absurd. " The Criminal Law Revision Committee acknowledged that a spontaneous statement "may have been made in haste and perhaps under the influence of shock caused by the events in question.
" It is also arguable that there may be a transitory opportunity for concoction between the incident happened and the statement made. The notion of contemporaneous state of mind means that courts will only allow statements of the present state of mind. As Roberts and Zuckerman stated: "English precedents are divided on the question whether a declaration of intention can be admitted to prove the intention was subsequently carried out. "
In R v Moghal , it was decided that declarations of intention fall within this exception to the hearsay rule despite contemporaneity as a matter of degree. Professor Dennis however said that: "It is very doubtful whether [Moghal ] can be taken as authority for any proposition of law. " It is therefore disputable whether 'declarations of intention' which are being used to prove that the intention was carried out are included within the common law's understanding of res gestae.  (a) Remediation of common law defects of res gestate by the statutory framework
The intention of the enactment of CJA was to nail down the common law rules. The Act formulated four accepted categories under which statements forming part of the res gestae are admitted: spontaneous exclamations, contemporaneous statements of physical sensation, statements accompanying and explaining an act, and statements as to the declarant's state of mind or emotion.  These specific statutory exceptions comprise most of the instances under which evidence may be adduced as res gestae and therefore, making it easier to admit such evidence.
In addition, the statutory code represents a more comprehensible regime particularly to the lay trier of fact.  It saves the courts time and efforts as there will be no need to inquire into the degree of contemporaneity of the statement as at common law and issues which do not serve to promote reliability.  It is also less likely to make mistake when applying the statute than there would be in applying the common law.
 In addition, with the new series of exceptions, legislature would no longer need to worry that the courts would continue to mess around with the rule and expand their "common law" exception of res gestae in an unsatisfactory manner. 44 The significant advantage of CJA is that common law method would no longer be able to shape the future law once the common law exceptions are codified into the statute.  Furthermore, CJA has further mitigated the uncertainty under common law when the preserved common law exception under res gestae provided that "if the statement relates to …
a mental state (such as intention … )".  This seems to have incorporated declarations of intention as an exception, and thus clarifying the previous vague position under the common law. (b) Problems arises under the statutory scheme Notwithstanding the comprehensive categories of res gestae exceptions formulated under CJA, it is arguable that hearsay evidence has been admitted despite its inherent dangers. In certain cases, the res gestae exception is allowed with only one circumstantial guarantee of reliability.
In others, admission of evidence on grounds of necessity has led to dangers of insincerity, especially statements of emotion or intent since no one other than the declarant can know what he was feeling. This shows that evidence is again admitted on a poorly constructed basis. The imperfection of the test put forward by the relevant res gestae exception is that the court will look no further than that in deciding on the admissibility of evidence. This prevented the court from exploring deeper into the strength or reliability of the particular evidence.