It will become the second toll road in Britain - following the M6 in Staffordshire - and will run between junctions 23 and 29 of the M4 to relieve congestion on the outskirts of Newport.
The newspaper reports that the Chancellor will agree to guarantee loans for the building of the M4 relief road, but the devolved Welsh government will meet the cost - expected to be around £830 million.
More top news
Liam Williams admitted that he loves "having a run" after setting up one of the greatest tries in British and Irish Lions history.
Rain and drizzle will clear through the afternoon with drier conditions to follow and some late sunshine.
Rain overnight turning light and patchy in the morning.