Descriptions of the criteria for defamation seem widely to describe any statement that is communicated to a third party as being defamatory if they are (broadly speaking) false and harmful.
This seems to allow for the possibility that relatively private communications can be deemed defamatory, even though most high-profile defamation cases involve public statements accessible to large if not unlimited audiences. Of course, the smaller the audience the more unusual it seems likely to be that such a communication could meet the serious harm test of the Defamation Act 2013, yet it doesn't seem impossible that the right lie told to the right person could yet have serious enough consequences to be defamatory.
Are there examples of very small-scale communications that have been tested for their ability to defame?
Tagged england-and-wales since inspired by Nigel Farage's claim that internal correspondence shared internally between employees of a bank were defamatory, but other jurisdictions welcome too.