Not The Least of Which

Today I stumbled upon a phrase in a plane crash news report and found it worth taking notice.

Here is the news:

"The account offered Saturday night by the U.S. safety agency - based on interviews conducted with the plane's crew - had numerous startling elements, not the least of which was the fact that Sullenberger, who has been hailed by the mayor of New York and President George W. Bush for his skill and bravery, was not at the controls at takeoff."

not the least of is a phrase used when you are giving an important reason for something, or an important example of something.

Here are some examples for this phrase:

There were several reasons for dismissing him from his post．not the least of which was his neglect of duty.

There are many drawbacks to the use of conventional shrink films, not the least of which is corrosion.