Criminal Defence

For free advice and quotations please contact 

OR call

Southern Office (London) +44 (0)203 397 4212                        Northern Office (Leeds) +44 (0)113 880 0780


Principal Forensic Services is composed of leading scientists all internationally recognised and among the most highly respected specialists in their fields. PFS has global experience of providing independent expertise to all parties including expert witness testimony commissioned by both Defence and Prosecution.

We have been instrumental in developing industry standards across the forensic science spectrum and have been commissioned by the Home Office Forensic Science Regulator to contribute to many aspects of the Regulator’s Guidance published as appendices to the Forensic Science Regulators Codes of Practice and Conduct. Quality, rigour and balance are central to all PFS work.

We provide the highest quality independent scientific review service utilising an unparalleled experience and talent profile.

  • What does the prosecution’s forensic evidence mean?
  • Is it fair, balanced and robust?
  • What are its weaknesses?
  • Was it conducted correctly?
  • Are there alternative explanations?
  • How might it be interpreted given your client’s account?
  • Could the evidence have arisen innocently?
  • Does the work done fully address the relevant issues?
  • Is it properly considered or is there only a Streamlined Forensic Report?
  • Have the scientific methods used been appropriately validated?
  • DNA
  • Blood/Body Fluids
  • Blood Patterns
  • Sexual Offences
  • Forensic Pathology
  • Statistical Interpretation
  • Drugs and Toxicology
  • Firearms
  • Gunshot Residue
  • Marks and Traces
  • Fire Investigation
  • Questioned Documents