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Forensic Science: Core Foundation Principles for Forensic Science Providers

updated 8 November 2019|Legal Guidance


This paper sets out the core foundation principles that must inform any potential providers of forensic science analysis for use in the Criminal Justice System (CJS). Such forensic science providers (FSP) may include private companies, government agencies, public organisations, academic research departments and law enforcement agencies, whether based domestically or internationally.


This brief summary highlights the Crown Prosecution Service (CPS) essential considerations when deciding whether a scientific product or service could be used as evidence in a case in England and Wales.

Core Foundation Principles

Statue and Case law in the jurisdiction of England and Wales

All prosecutions are conducted according to the law of England and Wales.

The Code for Crown Prosecutors

This is the Code that all Crown Prosecutors in England and Wales (along with a number of other prosecuting authorities) must apply when considering every prosecution throughout the life of the case. Application of the Code for Crown Prosecutors has two stages:

  • The Evidential Stage, and
  • The Public Interest Stage

The Evidential stage must be satisfied before the Public Interest stage can be considered.

The Code for Crown Prosecutors is available here on the CPS website.

The Crown Prosecution Service Casework Quality Standards

There are four over-arching principles which set out what the CPS does, how it makes decisions and what can be expected of the Service.

The Casework Quality Standards are available here on the CPS website.

The Criminal Procedure Rules

The Criminal Procedure Rules (CrimPR) were issued in 2015 and are revised every six months They apply to all participants, including expert witnesses throughout the conduct of a criminal case. Of particular relevance to forensic science service providers are:

  • Part 1: The Overriding Objective
  • Part 3: Case management: Identification of the Issues
  • Parts 21 and 22: Disclosure
  • Part 33: Expert Evidence

The Criminal Procedure Rules are available here on the Ministry of Justice website.

The Criminal Procedure and Investigations Act 1996, CPIA

In the course of any investigation, material divides into two parts, used and unused. Used material is the evidence in the case. Unused material is all the information generated by the investigation that is not being used as evidence. Investigators and prosecutors are obliged to consider all such unused material and apply the Disclosure test as follows:

  • Is the unused material relevant to the case?
  • If relevant, does the unused material either assist the defence case or undermine the prosecution case?

If the answer is 'yes', then the unused material must be disclosed to the defence.

To enable prosecutors to comply with this duty, FSPs must ensure that all material related to a prosecution is:

  • Recorded
  • Retained
  • Revealed

This information is explained more fully in the CPS Guidance for Experts on Disclosure, Unused Material and Case Management , Streamlining Forensic Case Management (SFR) and Proportionate prosecutions

Streamlining Forensic Case Management (SFR) and Proportionate prosecutions

This is a method of using consistent national case work principles to implement the requirements of the Criminal Procedure Rules when using forensic science in the CJS. It enables early identification of any forensic issues (CrimPR, Part 3) to take place much sooner in the case preparation process. It is a separate requirement to the CPIA requirement of a Defence Statement (in certain cases). The process also facilitates better compliance with CrimPR, Parts 3 and 19 wherein expert witness obligations and duties of disclosure are engaged much earlier in the process than previously.

Contracts, criminal law and the adversarial system

The distinction between criminal and civil justice systems must be recognised by commercial forensic science providers. It is important to understand that the Criminal Law 'trumps' Civil Law, including Intellectual Property Rights (IPR).

This is particularly relevant where the scientific providers are based elsewhere in Europe and may not be familiar with or structured to accommodate the Common Law adversarial system in place in England and Wales.

Specific rules apply in relation to the admissibility and reliability of evidence, along with the full disclosure of unused material - that is, any material relevant to the investigation that is not used as evidence (in accordance with the CPIA, see above).

Key Requirements for Forensic Science Providers

Key Requirements for Forensic Science Providers

There are five Key requirements for forensic science providers arising from the above Core Foundation Principles:

  1. To comply with the Codes of Conduct and Practice set down by the independent Forensic Science Regulator.
  2. To ensure Quality Standards and Assurance processes are applied which are nationally consistent and compliant with appropriate ISO standards, United Kingdom Accreditation Service (UKAS) accreditation, EU directives and clear development and validation processes.
  3. To provide clear communication and interpretation of scientific processes, procedures, strengths, weaknesses and meaning. This should be set down on a short (approximately 2 pages) guide in layman's terms to the key services being offered accompanied by a Question and Answer style document illustrating the strengths and weaknesses for the CJS of the scientific procedures offered. Not all Crown Prosecutors will necessarily have a detailed knowledge of forensic science. These documents will assist Prosecutors who are effectively 'gatekeepers' in the prosecution process when applying the Code for Crown Prosecutors, the CPS Casework Quality Standards, and the Criminal Procedure Rules to investigations and subsequent prosecutions.
  4. To engage with Streamlined Forensic Reporting (SFR) process associated with proportionate prosecution requirements.
  5. To be fully aware of and compliant with CPIA Disclosure and Expert Witness obligations (explanatory CPS Guidance for Experts on Disclosure, Unused Material and Case Management is available on the CPS website), including the disclosure of details of algorithms and statistical analysis, and without regard to commercial sensitivity. Following appropriate full disclosure of this information to the police and prosecution, the Court process allows for applications to be made to treat certain commercial information as 'sensitive' so that it cannot to be used for any purpose other than those particular proceedings.
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