The new 440m main span cable-stayed bridge will rank as the second longest bridge structure of its type in Wales and the fourth longest in the UK.

It forms part of a 23km new section of motorway between Junctions 23 and 29 south of Newport, crossing the Gwent Levels, River Usk Estuary, Newport Docks, the Llanwern Steelworks site and close to the Docks Way landfill site.

According to preferred joint venture contractor Costain/Vinci, which holds an ECI contract, the construction project would employ the equivalent of around 600 full-time workers.

The proposals also include new M4 junctions at Docks Way and Glan Lyn, and reopening the M4 Junction 25 at Caerleon.

It is hoped construction could start in 2018, with the section of new motorway opening in 2021.

The Welsh Government argues the M4 relief road would boost the economy, with the cost of delays to users on the motorway amounting to an estimated £78m a year.

The existing M4 motorway will be re-classified as a trunk road, once the new corridor is built.

In Spring 2016 the Welsh Government intend to publish the draft Statutory Orders and an Environmental Statement.

It is anticipated a Public Local Inquiry would be held later in 2016.