I have an HSBC account because at the time I moved to the Uk (2004) they had a mechanism in place so you could set it up as part of the application process. I don't remember the details but it was standard for everyone to just do it all before leaving NZ.

I bet a lot of people are in a similar position. Not that I really use the account now, I have a far happier time in my Barclays account. I actually have a real hate for HSBC.