The recession may have boosted this trend, he says, but it was not its primary cause.

ECONOMIST: Lawyers and your money

He also said that rising food prices were an aggravating factor of the unrest in the Middle East, although not its primary cause.

BBC: Food prices at dangerous levels, says World Bank

Zoellick also said that rising food inflation is part of the reason for the unrest in the Middle East and Northern Africa, although not its primary cause.

FORBES: Trading Food Inflation

The square windows on the original Comet jetliner were found to be the primary cause of its disintegration.

ECONOMIST: Aircraft fatigue

Sedgemoor District Council has said its "primary concern" is that the restructure will not cause extra costs to its taxpayers.

BBC: West Somerset Council: Plan for 'skeleton council'