The Welsh government says the completion date of the M4 relief road will not be put back, despite a delay to the start of the public inquiry.
Economy and Infrastructure Secretary Ken Skates has pledged that the scheme will still be completed in 2021.
UK government officials at the Department for Transport, have introduced revised methodology to their new forecasting for growth, an unexpected change not shared in advance with the Welsh government, which has necessitated a delay to the inquiry start date.
The public inquiry was due to commence on 1 November, but the changes made by the Department for Transport mean the inquiry will now not commence until the new year, allowing time for the new data to be considered.
The inquiry, which is expected to last around five months, will now start by 31 March 2017. It will examine all aspects of the M4 Corridor around Newport Project and take into consideration the most up-to-date and accurate information, as well as all suggested alternatives.
Mr Skates said: “The UK government has already expressed its desire to see work on the M4 project start as soon as possible, so it is hugely disappointing that the Department for Transport chose only to engage with us on these amendments to their traffic forecasting three days before they were introduced forcing this regrettable delay to the start date of the public inquiry.
“Whilst we push forward with our Metro plans for north and south Wales, the long standing and continued problems associated with the M4 around Newport need a solution that delivers a long-term, integrated and sustainable transport system.
“Assessments indicate that our proposed M4 project is the only reasonable solution, but it is only right and proper that the proposals are scrutinised robustly, transparently and openly in an inquiry and that we test the project in light of the most up-to-date information available to ensure that we deliver the right choice for the people in Wales.
“It is essential that we, and others who wish to submit evidence to the public inquiry, now take time to fully review these new Department for Transport figures before the inquiry begins.
“We’ve made a strong commitment to deliver a sustainable, long-term solution to the chronic traffic problems on this stretch of the M4 and I have been assured that, subject to inquiry approval, the M4 Corridor around Newport Project will still be completed in 2021.”