Activity from Opec’s largest members reached a frenzy this week as the 22 June meeting heaves into view. All indications are that Opec and the 10 cooperating ‘non-Opec’ states will seek to loosen production restrictions later this month. But the devil is in the detail and with Opec’s statute requiring a unanimous decision for production increases there is plenty of room for any prospective agreement to collapse.

The current production restrictions have been in place...