I participated in a ‘non normal’ flight-experience exchange involving the Lightning and Mirage. This provided ‘minimum supervision’ flights in the Mirage 3B in return for hosting similar flights in a Lightning T5.
After a flight involving single engine ops (low level PIs and ccts) I recall the French pilot asking why the Lightning needed two engines!
Both types were good interceptors, but both had limitations in tight maneuvering combat – Lightning high wing loading, Mirage high induced drag.
Any argument over the differences between a dog fight vs interceptor might come down to the range capabilities of the radar and missiles (rules of engagement); I suspect that the Lightning would win on range - interceptor, but concede to the Mirage in a gun fight.
The Mirage was subsequently developed as a multi-role aircraft; politics, and being prepared to accept a performance loss with a stores load. The UK had (or wished to develop) other types for the low level role, thus did not expand the Lightning’s capabilities until the Middle East market was opened up. Interestingly this was preceded by the Venezuelans who flew the T5 in comparison with the Mirage. Their pilot was impressed by the Lightning’s performance, but politically the requirement was for a multi-role aircraft.
For me, the Mirage was a fun aircraft to fly; the Lightning was a great aircraft to operate (which includes fun flying). The Lightning would have provided formidable defense in the classic cold war scenario, the Mirage more suited to the modern day ‘skirmishes’, thus it might be said that the Mirage had greater design (development) foresight than the Lightning, but that’s an issue for the air-staff … and politics, not the aircraft.