Despite being referred to heavily throughout the show, he has, so far not appeared physically in the show.
He appears to have attended Dartmouth University with Mark and Jeremy, having "put his pants on the taxi driver's head and he couldn't see a thing" on the way back from 'Cinderellas', at which time Mark was "literally weeping with fear."
He is known to have given his wife an 'aggressive' yeast infection from an Estonian prostitute, with whom he apparently had sex during his stag do.
He has at some point worked at HMV.
Jeremy mentions in Series 9, while explaining to Mark how he's "always been a bit gay" that during their time at university together, he and Pej "used to get pissed and pull each other off."
Behind the Scenes
At the Guardian Members screening in November 2015 the writers said they have received tweets over the years asking about Pej and that they did discuss meeting him in series 9. David Mitchell commented that Big Suze started out the same way as a reference to an unseen character who was eventually shown on screen. He also joked that when the show finally comes back after a 10 year absence it would centre on Pej