Saudis invest $100bn in oil and political influence

While most of the world is cutting back on oil investments, Saudi Arabia has quietly achieved a formidable feat of engineering - increasing its oil production capacity to a record 12.5m barrels a day.

The size and complexity of the five-year, $100bn (€70bn, £61bn) project are unmatched in the industry, as is Saudi Arabia's willingness to postpone the gains the project will bring by keeping many of its oil spigots closed.

Today the kingdom pumps 8.3m barrels a day, keeping a third of its capacity shut down. The restraint of Saudi Arabia, and of a handful of other countries of the Arabian Gulf, has propped up oil prices. Oil is trading at about $70 a barrel, very close to where Saudi Arabia and the Opec oil cartel want it to be.