In this scenario, the Welsh Government would either need to operate with a reduced budget or find alternative ways of raising such revenues to maintain existing resource levels.
Yn y senario hon, byddai angen i Lywodraeth Cymru naill ai weithredu â chyllideb lai neu ddod o hyd i ffyrdd eraill o godi refeniw o'r fath er mwyn cynnal y lefelau presennol o adnoddau.