Do Student Loan Debts ever get wiped out???

[welshgirl1]

If you owe student loan co a few thousand pound but never get to point where you are earning over the threshold ot pay it back does there ever come a time when loan is wiped out?? It worries me that interest is going on yearly but cos I aint hit the threshold I havent started paying it back, I know you can repay it early but I can't afford too in my present situation...could I potentially be paying it back when I am 50 or does there come a time when its wiped out???