Last-minute and late night telephone calls involving senior Opec and Russian leaders played a key role at various stages of the lengthy deliberations.
The first sign of a breakthrough came in March, when Saudi Arabia and its Persian Gulf allies held a ministerial meeting outside Opec’s purview in Doha.
That gathering looked like it was about to produce agreement, with Iran being allowed to restore most of its pre-sanctions output, but failed at the last minute when Saudi Arabia decided Iran could not be left out.
The
