INVESTMENT manager Brooks Macdonald has expressed doubts that the production discipline which has helped control oil supply and demand can be maintained in the long term.

The firm said that while a production cut instigated in December by the Organisation of Petroleum Exporting Countries (OPEC) cartel and Russia, which expires in June could be extended, an agreement would not be easy.

Robin McAdam, head of Brooks Macdonald’s Edinburgh office said: “Additional production cuts are likely to be difficult to agree. Furthermore, we would question whether the production discipline that has appeared in recent months can be maintained over the longer term.”