I just had a Skype interview at a university for a PhD position. The lecturer knows me by name and he taught me for a semester as an undergrad so we know each other very well. He briefly spoke to me in the corridoor a couple of days after and said he wants to consider me for the project but it's not official so I'll have to wait for a decision. My question to you is-should I follow this up with an email or let it lie?

Do not follow up. Just wait.

Cheers. I wasn't going to ask details but rather say thank you for considering me and offering me the interview. I couldn't believe he said that, I didn't think I'd performed very well.