Erbyn 2018, bydd yr arenillion o ddwy dreth y DU y bydd y trethi datganoledig yn eu  disodli yn debygol o fod tua £300m.  Bydd angen inni sicrhau bod y trethi newydd – a fydd yn elfen fach ond arwyddocaol o’r cyllid cyffredinol sydd ar gael ar gyfer  gwasanaethau cyhoeddus yng Nghymru – yn cael eu casglu’n ddiogel. A bydd arnom angen trefniadau hefyd sy’n galluogi trethdalwyr i gydymffurfio â’u rhwymedigaethau mor ddidrafferth â phosibl.
By 2018, the yield from the two UK taxes which the devolved taxes will replace is likely to be around £300m.  We will need to ensure the new taxes – which will be a small but significant component of the overall funding available for public services in Wales – are collected safely and securely.  And we will also need arrangements that enable taxpayers to comply with their obligations as straightforwardly as possible.