In September 1970 - often referred to as “Black September” - Jordan was in upheaval as the PLO essentially tried to take over the country. King Hussein responded by killing thousands of Palestinians and forced the PLO leadership to flee to Lebanon.
On September 6, two PFLP terrorists attempted to hijack an El Al plane from Amsterdam to New York. One terrorist was killed while the other, Leila Khaled, was wounded. The same day, other PFLP terrorists commandeered three different planes and flew them to Amman. After removing the passengers, the planes were blown up.
Hussein was humiliated and his throne was in danger. In response to fears that the hostages would be killed and Hussein dethroned, Britain agreed to release Khaled in exchange for the hostages. Six other terrorists in prison for previous attacks were freed from Switzerland and Germany as part of the deal.
Click HERE to read the documents
Sources: British National Archives