Qatar not denying it is half way to authenticating it.
Audio recordings get you 90% of the way.
Carefully checking transcripts and metadata for errors gets you further still.
Managing to get the same transcripts from the intelligence agencies of another country (either legitimately by asking, or covertly through "journalistic contacts") takes you to 99%...
You can never be 100% sure, but presumably the above met the BBC's standards for reporting.
Comments
How do you even authenticate the info if it's from a hostile government?
Qatar not denying it is half way to authenticating it.
Audio recordings get you 90% of the way.
Carefully checking transcripts and metadata for errors gets you further still.
Managing to get the same transcripts from the intelligence agencies of another country (either legitimately by asking, or covertly through "journalistic contacts") takes you to 99%...
You can never be 100% sure, but presumably the above met the BBC's standards for reporting.