The First Minister has told assembly members he cannot announce the decision on the proposed new motorway south of Newport until after the Newport West by-election has taken place.
Mark Drakeford said that it has been made clear to him that civil service rules on "purdah", an election period when major announcements are banned, affect the Welsh Government - even though it's a Westminster by-election.
The Government is unable, prevented by the right-and-proper rules, from making an announcement that could have an impact upon a local by-election of that sort. I am unable to make any announcement until that by-election is concluded.
He was answering a question from the Conservative leader, Paul Davies, who accused Mark Darkeford of making "one excuse after another".
Successive Welsh Labour Governments have dithered on this topic for nearly 20 years, you are still struggling to find the accelerator and deliver an answer to the nation. Welsh businesses, commuters, and others have come forward in support of a relief road for this choking artery at the heart of Wales's economy. And yet, despite paying £44 million for this inquiry, we're still waiting for a commitment from you and your Government.
Mr Davies said the First Minister should release the recommendations of a public inquiry into the project to reduce congestion on the M4 through Newport - believed to cost £1.4bn.
Mark Drakeford said last week that he had started reading the report of the inquiry inspector, which is over 500 pages long.