Hi guys, many thanks for your replies. Yes, I'm from
one of the countries in which even tourists need a visa, obtained in advance, to enter the UK.
I have completed my online application, and will go and submit all relevant documents at the Toronto office on Thursday. I have chosen to apply for a General Visitor Visa. For purpose of visit in the application I wrote 'visit xxx university and give a talk.' I guess this won't make much a different. I will ask people at the Application Center to make sure.
My main concern is how much time it needs to get my visa application approved and delivered back to the application center. The priority service at Worldbridge
https://www.visainfoservices.com/pages/content.aspx?tag=Services_page says 48 hours, plus its time on the way. I've heard people cancelled their interview due to visa issues. That's too bad...
I'll definitely ask people at the Application Center for more details. Except that, there seems not much I can do, except pray for good luck.
Should I email the university that I have this visa concern? How likely is that they'd postpone the interview to accommodate such issues? I wish they had let me know one week earlier.