Another point... don't hand in your notice until you're sure of your job.  If at the interview they ask you when you could start, mention that it could be month out or it could be sooner, that you'd have to get back with them to verify.  This allows you to then talk to your current employer and find out if they require that 4 weeks (1 month) notice or only 2 weeks (which is what I've heard more of here in the US).  It also shows the perspective employer that you want to do what's best for both employers... the future and the present.

Good luck on the interview!

CountriGal
Peer Moderator