The Welsh Government has confirmed that it will hold an independent public local inquiry into plans to build a relief road for the M4 in South Wales.
It said an independent inspector would ‘review the need for the scheme and consider all environmental, social and economic factors’.
Economy and infrastructure secretary Ken Skates said the inspector would comprehensively review the proposals for the favoured ‘black route’, in addition to considering suggested alternatives.
Earlier this month, UKIP dropped its opposition to the controversial ‘black route’, boosting its chances.
Mr Coates said: ‘This independent inquiry will set out the proposals for the M4 Corridor around Newport project in a public forum. It will allow open and transparent scrutiny and provide vital feedback to inform a final decision on whether to proceed to construction.
‘Alongside infrastructure improvements to the North, Mid and West Wales, the M4 project and the Metro are hugely important to our vision for an efficient, integrated transport system for Wales and I’m very pleased to have been able to move forward so quickly with this.’
The inquiry is due to start in Newport this autumn and is expected to take around five months, with a pre-inquiry meeting taking place on 18 July.
If the inspector recommends that the scheme should proceed to construction, the new section of M4 could be open by Autumn 2021.
James MacColl, head of campaigns at Campaign for Better Transport, said: 'The M4 Black Route would be a disaster for nature, climate and public health. The Public Inquiry needs not just to look at less damaging road options, but how we use rail freight and public transport alternatives to get unnecessary journeys off the roads and reduce congestion.
'The new administration should abandon this expensive and damaging road project and unite people behind better alternatives.'