It was on the night of 14 April 1986 that United States military aircraft took off from RAF Lakenheath and RAF Upper Heyford on a mission to bomb targets in Tripoli and Benghazi. Operation El Dorado Canyon was ordered by President Ronald Reagan in retaliation for the bombing of the La Belle discotheque in Berlin on 5 April in which two US servicemen were killed and 79 injured. Those who accept that Libya was responsible for the destruction of Pan Am 103 over Lockerbie twenty months later regard this US operation as supplying the motivation.
The Wikipedia account of the La Belle disco bombing can be read here. Among those who question whether Libya was responsible are former Mossad case officer Victor Ostrovsky in his The Other Side of Deception (1994 -- the relevant passage can be read here) and William Blum in his Killing Hope (updated to 2008 -- the relevant chapter can be read here).