The 30-year-old found game time hard to come by at Scotstoun last season, with the likes of current Scotland internationals Alex Dunbar, Peter Horne, Huw Jones and Nick Grigg all competing for places.
Having agreed a switch to Championship side London Scottish, Vernon feels it was the right time to move on to pastures new and is now looking forward to getting started with the Exiles.
He told The Rugby Paper: "I didn't get anywhere near the opportunities I'd have liked at Glasgow last season so it's time to move.
"The big decision was whether to retire or whether I've got another year left in me, but I had some great conversations with (rugby director) Dave Morris and chairman Malcolm Offord at London Scottish and realised I could add my experience.
"Importantly, I'll do a couple of days each week working in the City alongside my rugby and the move ticked a lot of boxes. I'm looking forward to the challenge and want to enjoy playing at what is still a really good level."