My husband has been a long standing RBS client, and that is where we got our joint account, however the situation surrounding it was a bit weird, so I'm not sure what the actual rules are.
We went in and met with one of their advisors and she said that in order to open the joint account with debit card/cheques etc., I would have to open my own account first. This was fine with us, because she was offering to open a good account for me (debit card, credit card and all) and because we had the necessary proof of address (I was a student here in the past, so had an old NatWest bank account statements being sent to my new address).
A couple of weeks later, we got a call from RBS saying that that employee had left, and that she had messed up some of our paperwork for our joint account. At that point my personal account was all set up and I had received the cards/cheques. We went in and filled out the correct paperwork for the joint account, and we now have that all set up as well (we both have Maestro cards for it, and it comes with a special savings account as well).
It's not clear if the original employee was correct in that I needed to set up my own account first, since she muddled up the rest of the application so badly. We didn't question it with the second person we met with, because at the end of the day I'm happy to have my own account as well. All in all the process took over a month between filling out paperwork/ receiving checks and cards/going in to the branch for pin numbers etc.