Oil prices fell sharply today after world powers struck a landmark deal with Iran to curb its nuclear programme in exchange for an easing of international sanctions.
While Iran will not be allowed to increase its oil sales for six months, any easing of Middle East tensions tends to lead to lower crude prices.
When you consider the diplomatic mountain the US and Iran have already scaled, you get a daunting sense of the challenge ahead.
The deal between Iran and world powers looks like a breakthrough, but with six months of wrangling over details ahead, it could still fail.
The nuclear agreement between Western powers and Iran was broadly welcomed by politicians, former world leaders and Middle East experts.