Parties to litigation sometimes wish to rely on evidence of similar but unconnected past incidents, arguing that what happened then is a good indicator of what happened in the case in question. Such evidence of “similar facts” is tightly controlled in criminal cases, but the test for its admission in civil cases is less stringent.
A recent decision in the high profile Mitchell “plebgate” case illustrates the court’s approach. Here the court agreed to admit evidence of Mr Mitchell’s past encounters with police which, if true, might throw light on his attitude and reaction when impediments were placed in his way by police officers and therefore support the defendant’s case: Mitchell v News Group Newspapers Ltd  EWHC 3590 (QB).
That is not to say that similar fact evidence will always be admitted in civil cases. The court must balance the probative value of the evidence against any potential unfairness it might cause, as well as the additional burdens in case management terms. Where the balance lies will depend on the circumstances in each case.
The underlying litigation is a defamation claim brought by Andrew Mitchell MP against News Group Newspapers in relation to its reporting of the notorious affair at the gates of Downing Street in September 2012, in which Mr Mitchell was said to have sworn at police officers and branded them as “plebs” and “morons”. The relevant police officer, PC Rowland, also sues Mr Mitchell in respect of his statements to the effect that PC Rowland fabricated his account of the incident.
In their statements of case, NGN and PC Rowland relied on seventeen alleged previous encounters with police officers in which Mr Mitchell had behaved in a rude, arrogant or condescending way. Mr Mitchell applied for an order excluding this evidence (save for two such matters which Mr Mitchell accepted were relevant for other reasons) on the grounds that it was inadmissible, or alternatively that its probative value was outweighed by its potential for causing unfair prejudice and that it placed a disproportionate burden on Mr Mitchell.
Mr Mitchell said the evidence added nothing in light of his admission and averment that he “on occasion was impatient and short-tempered with obstructive or otherwise unhelpful police officers” and “very occasionally he was (or may have appeared to have been) rude, or used swear words when speaking to those officers”.
The judge (Warby J) held that the evidence should be admitted, save in respect of six allegations which he ruled out as falling short of the threshold of potential probative value.
It was common ground that the relevant principles were established by the House of Lords in O’Brien v Chief Constable of South Wales Police  2 AC 534, which set out a two-stage test:
- First, whether the evidence was relevant, in the sense that it made some matter which had to be proved in the case more or less probable. If so, then the evidence was legally admissible.
- Second, whether the evidence should be admitted as a matter of case management. This would depend on such factors as whether it would distract the attention of the decision-maker or cause unfair prejudice (in each case particularly if the trial was to be by jury) and the burden it would place on the resisting party, eg in relation to disclosure, trial length, fading witness recollections, etc.
Here, the judge accepted that the evidence, in relation to the majority of the incidents, was relevant. He noted that although the central issue was whether Mr Mitchell spoke the “toxic words”, that allegation had to be considered in its context. Disputed issues of detail in the competing accounts might be important. The judge accepted the submission that the evidence of past incidents, assuming it provisionally to be true, might lead to the conclusion that the events in question were more likely to have unfolded as alleged by PC Rowland and NGN, rather than Mr Mitchell.
As for the discretion to exclude the evidence (stage two referred to above), the judge concluded that the evidence should be admitted. He did not believe the trial would be distorted or unbalanced by the admission of the evidence. The incidents alleged were all relatively brief, and the evidence quite narrowly confined, and so the evidence should not take up a great deal of time at trial. He also did not consider that there would be unfair prejudice to Mr Mitchell. The trial judge could give appropriate weight to the evidence, making due allowance for the passage of time and any restrictions on Mr Mitchell’s ability to challenge what was said (since he could not remember most of the incidents).