As a student I recommend opening a Canadian HSBC account in Canada before you leave for the U.K. A friend recommended that I do this and I'm glad that I took his advice! I received my Canadian HSBC debit card right in the bank upon opening my account, and made sure to set up email money transfers from my regular Canadian bank account (not HSBC) so that I could receive money in my new HSBC account.
I flew to the U.K. and was able to use my Canadian HSBC debit card in HSBC machines without charge (many Marks&Spencer debit machines are also HSBC machines). I then went about setting up a U.K. HSBC account. In order to do this I went to the bank and made an appointment to set up an account. They asked for the following documentation: letter from my University confirming full-time student status, proof of my address in the U.K. (a letter from U.K. agency with your name and address, I used a bill), and my passport (including my student visa).
The process is not instantaneous as you will have to wait until you are a bit set up and can receive a bill or some other proof of your address at your address in the U.K. If you have access to your funds though (as I did through my Canadian HSBC debit card), this method could work.





