Postgraduate loans- interest

Hello,
With the new postgraduate loans, repayments will not begin until April 2019. Does this mean that the loan will be accruing interest from when we are paid it and will continue to do so until we the repayment systems come into place?
It seems incredibly unfair that we will be charged interest when there is no opportunity to pay back our loans as soon as the course finishes. Or will there be an option to pay it back voluntarily following the completion of the masters course.

Thanks,
Abby