Short version: If you're a science fiction/fantasy writer who got an invitation to speak from Bexley College in the UK, someone's trying to scam you.
Here's an e-mail in my box today:
Greetings John Scalzi,
I am Prof. Arthur Peterson from Bexley College (Holly Hill Campus) here in London UK. We are officially writing to invite you and confirm your booking as our guest Speaker at this Year Bexley college Seminar which will take place here at the campus ground.