Non Accidental Head Injury Cases (NAHI, formerly referred to as Shaken Baby Syndrome [SBS]) - Prosecution Approach

Legal Guidance, Domestic abuse , Violent crime


This guidance is intended to provide information on the stance taken by the Court of Appeal and the High Court in relation to Non Accidental Head Injury (NAHI) cases and to assist prosecutors in the approach and presentation of such cases.

The use of the term 'Shaken Baby Syndrome' should now be avoided as it can be considered to have emotive connotations, and more importantly, does not adequately describe the range of causes of head injuries.

A glossary of terms and abbreviations used in this guidance is contained in Annex G.


Each case will clearly turn on its own facts. In a case where the child dies (or suffers severe injury), it is unlikely that a charge for a homicide (or attempted murder or assault) offence could be justified where the only evidence available is the triad of pathological features; appropriate supporting evidence (which in certain circumstances can be found in the absence of certain factors) should feature in the case analysis.

In gathering evidence in such cases, it will be important to obtain as much supporting details as are available. In particular, clinical evidence and evidence of the nature of the shake/fall/impact etc may be critical in assessing the prosecution case. The expert evidence finding of typical triad pathological features might not be considered as diagnostic in itself but simply as strong evidence that the injuries were non-accidental.

All the surrounding evidence must be fully considered by the prosecutor before a decision can be made on the evidential sufficiency in accordance with the Full Code Test in the Code for Crown Prosecutors.

The level of charging will have to be considered carefully in light of the comments in Allen [2005] EWCA Crim 1344 and the Harris and others [2005] EWCA Crim 1980 (see Annex A) judgments regarding whether the necessary intent can be inferred from the force that is believed to have been used. See also the judgment of the Court of Appeal in R v Burridge [2010] EWCA Crim 2847.

In appropriate cases where death has occurred, prosecutors may wish to consider charging under section 5 of the Domestic Violence, Crimes and Victims Act 2004 as well as murder or manslaughter. Guidance on the implications of this can be found in the CPS Legal Guidance on Homicide: Murder and Manslaughter.

Synopses of relevant authorities from the Court of Appeal and the High Court are set out at Annex A to this guidance.


On 19 January 2004 the Court of Appeal gave full judgment in R v Angela Cannings [2004] EWCA Crim 01 case. The judgment related to the death of infants where there were no obvious external injuries and the issue revolved around expert evidence as to whether the death was as a result of intentional suffocation or due to some unknown reason, termed sudden infant death syndrome or "SIDS".

The Court of Appeal (Judge LJ) concluded at paragraph 178 that if:

"the outcome of the trial depends exclusively or almost exclusively on a serious disagreement between distinguished and reputable experts, it will often be unwise, and therefore unsafe, to proceed."

As a result of the Cannings judgment, reviews of past and existing cases involving sudden unexplained deaths in infants were carried out by the then Attorney General and Director of Public Prosecutions to ensure that there were no further cases of the type described in the Cannings judgment.

However, Judge LJ later clarified that this approach was not to be applied to NAHI cases in his judgment in the case of R v Kai-Whitewind [2005] EWCA Crim 1092 at paragraph 84, Judge LJ commented:

"In reality, the problem with the argument based on paragraph 178 of Cannings outside its context, is that carried to its logical conclusion, the submission would mean that whenever there is a conflict between expert witnesses, the case for the prosecution must fail unless the conviction is justified by evidence independent of the expert witnesses. Put another way, the logical conclusion of what we shall describe as the overblown Cannings argument is that, where there is a conflict of opinion between reputable experts, the expert evidence called by the Crown is automatically neutralised. That is a startling proposition, and it is not sustained by Cannings."

And at paragraph 89, Judge LJ further stated,

"Cannings does not produce the result that it follows from an argument between experts that the issue whether the fracture occurred after or before death, or whether there is a fracture at all, is not appropriate for a jury's consideration. Evidence of this kind must be dealt with in accordance with the usual principle that it is for the jury to decide between the experts, by reference to all the available evidence, and that it is open to the jury to accept or reject the evidence of the experts on either side."

What are the features of Non Accidental Head Injury (NAHI)?

Non-accidental injuries can be caused to a child's head in a number of different ways, including impact from a physical strike or implement. The pathological features of NAHI in children often include a triad (sometimes referred to as 'the Triad') of intracranial injuries consisting of:

  • Retinal haemorrhages (bleeding into the linings of the eyes);
  • Subdural haemorrhages (bleeding beneath the dural membrane);
  • Encephalopathy (damage to the brain affecting function).

The mechanisms causing these injuries are not completely understood. From confessional and other evidence it may be shaking (rotational acceleration and deceleration forces) of the infant, with or without impact on a firm surface, which moves the brain within the skull, damaging the brain and the shearing of superficial veins on the surface of the brain, producing subdural haemorrhage. A similar causation may be responsible for retinal haemorrhage.

There is some evidence to suggest that suspects in NAHI cases sometimes confess to 'shaking', as this may be perceived as minimising their criminal act, rather than admitting to hitting or striking the child.

The triad of pathological features is central to the diagnosis of NAHI, particularly when there are no other signs or symptoms of trauma such as bruises or fractures. Other features include the fact that the injuries are usually inflicted by a sole carer in the absence of any other witness. The injuries can also be associated with rapid apnoea (cessation of breathing) and unconsciousness. These are commonly followed by an inadequate history or account, incompatible with the severity of the injuries.

It is important to recognise that although the medical evidence is crucial to prosecutions in NAHI cases, other non-medical facts are important and can provide appropriate supporting evidence in addition to the triad of injuries. These additional factors or areas that could support NAHI may include:

  • History of violence towards children
  • Previous atypical hospital visits of the deceased child or siblings
  • Appearance of atypical bruises or fractures
  • Inconsistent accounts
  • Mental health issues
  • History of domestic, alcohol or drug abuse
  • Deceased or sibling on child protection plan / known to children's social services
  • Previous (or subsequent) death of sibling
  • Drugs present in deceased e.g. as revealed through toxicology or analysis of hair samples
  • Conflicting accounts for time of death
  • Previous convictions on the part of suspects, particularly for offences of violence and/ or domestic abuse

For further reading, see:

Wate, R and Marshall, D. (2009). Effective Investigation of Intra Familial Child Homicide and Suspicious Death. The Journal of Homicide and Major Incident Investigation, volume 5, issue 2. ACPO/NPIA: London.

Risk Factors for Intra-familial Unlawful and Suspicious Child Deaths: A retrospective study of cases in London. Mayes, Brown, Marshall, Weber, Risdon, Sebire (2010)

The Challenges to NAHI

The challenges to the mainstream interpretation of the triad are three-fold (and generally termed the 'unified hypothesis'):

  • First is the suggestion that brain hypoxia (lack of oxygen), infection or raised intracranial pressure can cause not only encephalopathy, but also subdural haemorrhage, and by implication, retinal haemorrhage. This is the so-called 'unified hypothesis' first put forward by Geddes (2004).
  • Second, it is suggested that accidental short distance falls can be associated with similar pathological findings (see 'Short Distance Falls' at Annex E).
  • Third, in the very young, a degree of subdural haemorrhage and retinal haemorrhage may be the result of a birthing injury (see also 'Subdural haemorrhage in the neonatal period' at Annex F).

However, it should be noted that the Court of Appeal rejected the "unified hypothesis" in the case of R v Henderson, Butler and Oyediran [2010] EWCA Crim 1269. See Annex A for further details.

For further reading, see:

Cohen, M.C. and I. Scheimberg. Evidence of occurrence of intradural and subdural haemorrhage in the perinatal and neonatal period in the context of hypoxic ischemic encephalopathy. An observational study from two referral institutions in the United Kingdom. Paediatric Developmental Pathology, 2008: p. 1.

Geddes JF, Plunkett J. The evidence base for the shaken baby syndrome. BMJ 2004; 328: 719-20. (27 March.)

Bio mechanical evidence

In addition, those challenging the triad approach may invite consideration of bio mechanical evidence. Before allowing the introduction of bio mechanics in evidence, there should be a requirement for those adducing it to prove an evidential link demonstrating the relevance and comparability of experiments on non-biofedelic models to real life incidents with live children. Please see Annex B for a fuller discussion.

Royal College of Pathologists (RCP)

On 10 December 2009, the RCP convened a meeting to consider the issues and key approaches of those holding the mainstream view of the 'triad' contrasted with those supporting the 'unified hypothesis in NAHI cases. The report of the meeting and its conclusions can be found at

The published report of this meeting is also attached at Annex C. The key conclusions are summarised as follows:

"The following list has been agreed by the participants at the meeting

"It was agreed that when the following features are all present at a paediatric post mortem:

  • widespread bilateral retinal haemorrhages and large macular folds
  • thin-film subdural haemorrhage
  • encephalopathy

(i.e. 'the triad' in characteristic form) then, considering the case in the absence of other evidence, there should be a prima facie suspicion that the injuries are due to mechanical trauma, potentially including vigorous shaking.

"It was agreed that all the individual elements of 'the triad' have a differential diagnosis, and that a thorough post-mortem examination is invariably needed to exclude, as far as possible, non-traumatic explanations of such changes.

"It was agreed that, based on current knowledge, the presence of 'the triad', even in its 'characteristic' form, should not be regarded as absolute proof of traumatic head injury in the absence of any other corroborative evidence."

Conclusion: The Triad of Injuries and The Unified Hypothesis

In the light of all the issues set out above, and in the annexes to this Guidance, the CPS view remains that any reliance on the so called 'unified hypothesis' to challenge the mainstream interpretation of the triad of pathological features should be subjected to thorough testing on the basis of the comments in the cases outlined in Annex A.

This Guidance is intended to set out a number of common issues raised in these complex and sensitive cases. Where a triad of injuries are found, the surrounding circumstances and evidential context of each case will always be considered on an individual basis. These considerations will always take place in line with the Code for Crown Prosecutors.

The Role of Experts

Whilst it is for the jury to evaluate expert evidence presented to it, the evaluation of the expert him/herself should clearly precede this.

The Kennedy Report (2004) "Sudden Unexpected Death in Infancy: A multi-agency protocol for care and investigation - The report of a working group convened by The Royal College of Pathologists and The Royal College of Paediatrics and Child Health" is widely regarded as the definitive review of the issues. It produced an approved, multi-agency protocol for care (of the parents) and investigation of such cases. In particular, it noted:

"It is also important that the courtroom is not a place used by Doctors to fly their personal kites or push a theory from the far end of the medical spectrum. The expert should have recent clinical experience, peer reviewed research and should not roam outside of his or her area of expertise.

"If the defence are able to call a 'quack', inappropriately qualified doctor or enthusiastic amateur and present their evidence as having equal value to that of a well established authority on a subject, another kind of injustice can be perpetrated.

"Judges should be proactive in exercising their duty to establish the expertise of witnesses appearing before them and should ensure that courts are not used to push a theory with an insufficient scientific base. Judges should also ensure that experts have recent clinical experience. The expertise of witnesses coming from outside of the jurisdiction should be tested with the same rigour as that of British experts."

Case Management and the Criminal Procedure Rules 2005 - 2010

These cases are usually complex and contentious. Where there is a difference of opinion between experts for the Prosecution and the Defence, it is vital that all expert statements are disclosed well before a trial commences.

Pre-trial Case Management

Strict adherence to, and implementation of, the regime provided by the Criminal Procedure Rules 2010 will facilitate clear steps being taken in the service, consideration and agreement (or otherwise) of expert opinions.

The primary purpose of robust pre-trial management is to narrow down the real issues, particularly those of a medical nature, which the jury must decide upon.

The following Rules are of particular relevance to the management of suspected NAHI cases:

1.1 The overriding objective is that criminal cases be dealt with justly

1.2 The parties must conduct the case in accordance with this objective and comply with the directions made by the Court

3.2 The court must actively manage the case, which means:

a. identifying early the real issues,
c. achieving certainty as to what must be done and by whom and when,
e. ensuring the evidence is presented in the shortest and clearest way,
g. encouraging co-operation by the participants,
h. making use of technology.

3.4 Case Progression Officers should be appointed to monitor compliance with Directions.

Expert Evidence: Admissibility

The Criminal Procedure (Amendment) Rules 2010 SI 2010 no. 60 deal with expert evidence. Ensuring strict compliance will assist in the understanding by the jury of the real medical issues in the case. Compliance will also enable a judge more efficiently to approach the question of admissibility of the expert evidence, in particular:

33.2.(1) The expert's duty to help the court to achieve the overriding objective by giving unbiased opinion on matters within his / her expertise.

33.3.(1) An expert report must provide evidence of relevant experience and accreditation (a), details of any literature relied upon (b), the facts used upon which to base the opinion (c), who carried out the work (e), summarise any range of opinion and give reasons for their own opinion(f), state any qualifications to their opinion (g).

33.6.(2) The court may direct that there is a meeting of experts and that a statement should be prepared of areas of agreement and disagreement ((a) and (b)).

33.6.(4) The court may direct that a party may not introduce expert evidence without the court's permission if the expert has not complied with this direction. See also the Note to 33.6.which reminds the court that there is the power to make binding rulings as to the admissibility of evidence at the pre-trial stage.

Once a strict timetable has been imposed on the parties in respect of the obtaining and service of expert reports (with funding for the defence having been put in place as quickly as reasonably possible), the designated judge may (and indeed should) order a meeting of experts well before trial (Rule 33.6).

It is difficult to imagine a case of alleged NAHI where a meeting of experts is not of real benefit.

A key purpose of complying with the CrPRs is, amongst others, to assist the jury by seeking to achieve an agreed document to go before them, setting out:

  1. where in the expert evidence there is agreement; and
  2. where there is not (and therefore identifying for the jury where there needs to be focused debate).

There needs to be acceptance that the result is a document that the experts for either side will not be permitted to go behind.

In R v Reed, Reed, R v Garmson [2009] EWCA 2698 Thomas LJ dealt with the complex science of admissible DNA evidence. There is useful guidance within that case that can be applied to cases of alleged NAHI.

  1. The court ordered that a "primer" or guide to the basic science applicable should be provided. There is no reason why such a document should not be agreed and provided to a jury in cases of NAHI (see Thomas LJ at paragraph 28).
  2. At paragraphs 128-133, Thomas LJ clearly set out and emphasised the importance of the use of and adherence to Part 33 of the CrimPRs.

In short the guidance set out in Reed (at paragraph 131) amounts to;

  1. Parties must provide identification of agreement and disagreement within the experts' reports.
  2. That notification of those areas of disagreement thereafter must be given to the court and the case then must be brought before the judge. This obligation falls to both the prosecution and the defence.
  3. The judge should then order a meeting of experts to take place.
  4. A statement under Rule 33.6 should be then drafted setting out in clear terms the agreed science, for use at trial.
  5. Any non-observance of an order for such a statement will be met in most cases by a refusal by the trial judge to admit the evidence of the expert not complying.

Parallel proceedings: Family and Criminal

Where there are associated family proceedings, as well as a criminal investigation / prosecution, see the Legal Guidance on Safeguarding Children: (Guidance on Children as Victims and Witnesses) for procedures on disclosing information into and from the Family Court proceedings.

Reference Material

The NPIA National Injuries Database is being used to compile details of all child homicide and suspicious child death investigations from police forces within England, Wales and Northern Ireland. This will act as a central reference point for others dealing with these types of cases and provide a source of data for research and analysis. For further information on this reference point, details relating to injuries and/or medical experts please contact the National Injuries Database on 0845 000 5463. Contact details can be found at the following link:

A number of cases where there are Family Court proceedings (in which expert evidence is given) may assist in relation to additional medical evidence or the credibility of those medical experts giving evidence. New Legislation - The Family Proceedings (Amendment) (No. 2) Rules 2009 and The Family Proceedings Courts (Miscellaneous Amendments) Rules 2009 - allow use of Family Court proceedings material as information for investigations or even in criminal court proceedings.

Further reading