Pwynt pwysicaf llythyr y Prif Ysgrifennydd yw bryd hynny ni ostyngwyd cyllideb Llywodraeth Cymru i gyd-fynd â'r gostyngiad i gyllideb Adran yr Economi, Trafnidiaeth a'r Rhanbarthau. Dyma'r tro cyntaf i Lywodraeth y DU ddatgan hyn yn gyhoeddus. Mae'n golygu bellach ei bod yn anodd parhau i ddadlau bod y broses honno'n anfanteisiol i Gymru.
The critical point in the Chief Secretary’s letter is that at that time no reduction was made in the Welsh Government’s budget that corresponded to the reduction in the DETR’s budget. This letter is the first time that the UK Government has put this on the record.  It means that it is now difficult to continue to argue that Wales was disadvantaged in that process.