Amcan cost atal a dileu'r atebolrwydd ôl-ddyddiedig yw tua £175 miliwn, ac o ganlyniad i benderfyniad Llywodraeth y Cynulliad i beidio ag atal atebolrwydd ôl-ddyddiedig yng Nghymru yn 2010-2011, mae'r Trysorlys eisoes wedi cynnwys swm ar gyfer cyllid canlyniadol, a allai fod yn rhyw £10 miliwn, o fewn yr adolygiad o wariant.
The estimated cost of the suspension and writing off of the back dated liability in England is around £175 million. The subsequent consequential for Wales is around £10 million and the Treasury has already included this sum for consequential funding within the spending review.