Thanks to Peter Taheri of 5 Essex Court for preparing this case summary
In a claim of unfair dismissal on grounds of misconduct, is an employment tribunal's failure to analyse whether the employer's investigation satisfied A v B  IRLR 405 an error of law?
No, held the EAT in Yeung v Capstone Care Ltd.
In A v B, Elias P held that serious allegations of criminal behaviour must always be the subject of the most careful investigation. While it is unrealistic and inappropriate to require the safeguards of a criminal trial, a careful and conscientious investigation of the facts is necessary.
In Yeung, Langstaff P held that although the general propositions set out by Elias P deserve re-emphasis, an employment tribunal does not have specifically to mention A v B in a claim of unfair dismissal based on alleged criminal misconduct. The issue is whether the statute has been satisfied or not. A failure to give a specific analysis by reference to one case, though significant, is not a failure to convey an explanation to the Claimant as to why she lost.
Two other noteworthy points from the judgment:
1) The Claimant had not taken part in the disciplinary hearing but, on appeal, raised points that the employer felt merited re-investigation. However, the employer did not revert to the Claimant post-re-investigation with the new evidence.
Despite recognising the potential breach of natural justice, the EAT dismissed the appeal and held that the employment tribunal failing to deal specifically with the appeal officer's omission to revert to the Claimant was not an error of law: The point had not been raised below. The employment tribunal, "though tersely", had considered the point: it noted that the new evidence "corroborated" that from the original investigation. The new evidence only supported that which the appeal officer already considered sufficient to determine the appeal against the Claimant.
2) Despite the employment tribunal's omission to make an explicit finding that the investigation was reasonable, the insufficient reasons challenge was dismissed by the EAT: The employment tribunal had expressly recognised the need to find the investigation was reasonable and "plainly" the employment tribunal had thought the procedure was a fair one. Enough was said to tell the Claimant why she lost the case.