loan interest fees and early repayment

mrs_moneyspinner

I borrowed 2 yrs ago to buy a car and signed up for a monthly repayment with the proviso that if I pay the loan off early at various points over the 3 year plan I must also pay interest that would have been due on the loan had it continued to the end of the term. I didnt read the small print at the time but that's what i signed up for - is it common practice and enforceablel? As we are having credit crunch probs it seemed sensible to pay off the loan with any cashflow so we reduce any debts outstanding but paying the interest that 'would have been' sticks in the throat a bit.