And it seems that perhaps Eurovision itself is partly to blame. The gay-friendly, kitsch and flippant song contest offended Iran’s sensibilities and last week it withdrew its ambassador from Baku for consultations because of what it described as Azerbaijan’s anti-Iranian and anti-Islamic policies.

Now news reports suggest the Azerbaijani government has ordered its envoy to return to Baku, also for consultations, after Iranian authorities apparently detained two Azerbaijani poets.

The Azerbaijan-Iran relationship has often been fraught, recently because of Azerbaijan’s budding friendship with Israel, Iran’s sworn enemy, and Iranian attempts to meddle in the region.

There have been rows and both sides have sent tetchy protest notes to each other but cutting diplomatic relations pushes relations to a new low that needs to be monitored closely.

Iran has carefully built up relations with Armenia, Azerbaijan’s enemy, and Georgia which means the Azerbaijan-Iran row raises tension across the entire South Caucasus.