The UK professor, a fake Russian spy and the undercover Syria sting

Ex-Observer journalist tells of role in trap to expose disinformation tactics of defenders of the Assad regime

A more sceptical academic than Paul McKeigue might perhaps have wondered if the emails flooding into his inbox from Ivan", a purported Russian spy, were too good to be true.

Ivan appeared to share many of McKeigue's own personal obsessions, particularly his desire to discredit investigators who compile evidence of war crimes committed in Syria. And he claimed access to both ready cash and secret intelligence.