As Opec ministers prepare to meet in Vienna, questions are being asked about the effectiveness of the strategy that puts long-term demand over short-term financial gain. Neil Hume, commodities editor, outlines what we can expect this week.<br /><br />► Subscribe to the Financial Times on YouTube: http://bit.ly/FTimeSubs<br /><br />For more video content from the Financial Times, visit http://www.FT.com/video<br /><br /><br />Twitter https://twitter.com/ftvideo<br />Facebook https://www.facebook.com/financialtimes
