Houston-based Cobalt International has decided to take Sonangol, Angola’s state oil company, to arbitration to resolve a long-running, multi-billion dollar impasse over the planned sale of the US company’s assets in the country, writes Iain Esau.

Cobalt has submitted two claims to the International Chamber of Commerce (ICC), demanding Sonangol pay it more than $2.17 billion.

The dispute harks back to August 2015 when Sonangol agreed to buy Cobalt’s stakes in pre-salt blocks 20 and 21 for $1.75