If your current account balance goes below zero, one of three things will happen.
You will dip into an arranged overdraft – you might have to pay to use it or you could have
an interest-free overdraft if that perk is included with your account
You will dip into an unarranged overdraft – your bank might inform you of using an
unarranged overdraft and penalise you through charges or daily fees
Your latest payment will not go through – whether it is a purchase made on a debit card or a
direct debit coming out of your account, it will simply not go through and you should be
notified