Mae'r cynnydd mewn costau ac oediadau i’r rhaglen sy'n gysylltiedig â chwblhau’r cynllun wedi cael eu dogfennu'n dda, gan gynnwys adroddiad interim gan yr Archwilydd Cyffredinol a sesiwn ym mis Medi 2020 o flaen y Pwyllgor Cyfrifon Cyhoeddus. Bu anghydfod cytundebol rhwng Llywodraeth Cymru a Costain ers 2018 ynghylch pwy ddylai dalu cost y cynnydd hwn. Gallaf gadarnhau bod Llywodraeth Cymru bellach wedi setlo ei dadl gyda Costain. Er y bydd manylion y setliad yn parhau i fod yn gyfrinachol, at ei gilydd mae’r broses o ddatrys yr anghydfod wedi cefnogi dehongliad Llywodraeth Cymru o delerau'r contract.
The cost increases and programme delays associated with the construction of the scheme have been well-documented including an interim report by the Auditor General and a session in September 2020 in front of the Public Accounts Committee. Welsh Government has been in a contractual dispute with Costain since 2018 about who should bear the cost of these increases. I can confirm that Welsh Government has now settled its dispute with Costain. While the details of the settlement will remain confidential the dispute process has been largely supportive of Welsh Government’s interpretation of the contract terms.