You know that part in "Parisienne Walkways" where he holds a bend for an eternity and doesn't lose any volume at all? How does he hold that note for so long? There's no vibrato...
i cant say i know the song but maybe a Fernandez Sustainer? ive seen steve vai use them and they seem to do what you've described...
I deeply regret the 6661 in my username. Siiiigh. Damn you, 14 year old me, you edgy little bastard.
yeah it's very likely he uses a sustainer

“If there was anything that depressed him more than his own cynicism, it was that quite often it still wasn't as cynical as real life.”
― Terry Pratchett


Jeremy Clarkson is a knob.
Feedback, an awesome Les Paul, and a compressor.
He doesn't use sustainer pickups.

I'm gonna say feedback too. With my amp set to a decent volume and my friend's les paul i got some infinite sustain going by just leaning the guitar body against the amp and using vibrato. Then people told me to shut up after a few minutes cos it was getting annoying
I have seen the guy play it live and it is not feedback. It is just top class gear with a sustainer unit. Very few artists allow a note/chord to ring as long as Moore so I am not surprised that it takes people by suprise. However his tone is created by wonderful vibtrato and tasteful phrasing. A lot of it learned from the Fleetwood Mac founder Peter Green - who I think was the best ever in that regard. Someone that underplayed rather than the more normal overplaying.
Stop showing off and play the music!
Also, wasn't his guitar crafted by Chuck Norris as blessed by the pope?