CALLS for a decision on the M4 relief road to be made by Carwyn Jones' successor as first minister have received unanimous support from AMs.

Mr Jones has repeatedly insisted he will make the decision on the long-awaited scheme before he leaves office on Tuesday, December 11. But late last week he suggested he may not be able to do so.

And earlier today, Wednesday, a motion presented by Plaid Cymru calling for the decision to be left to his successor was nodded through without opposition.

Presenting the motion, Plaid's Rhun ap Iorwerth said: "Our simple point today is that the decision should be left to the new first minister as to whether we proceed or not, because we believe that the decision is so significant that the decision should be owned by whoever becomes the new first minister of Wales.

"We don't believe that it’s acceptable for either the current first minister to take the blame for doing something unpopular and then to disappear off the scene, or to take ownership of this as some means of leaving a personal legacy.

"No, there is too much at stake here, and it should be a decision taken by the person who replaces the current first minister."

But the vote is not legally binding, meaning Mr Jones could still make the decision before he leaves office.

The decision Mr Jones is due to make is whether or not to give the go-ahead for the new road to be built. A second decision on whether or not to release the funding to pay for the project will be made at a later date by the new first minister.

Among those to speak in support of the motion was Ukip's Neil Hamilton, who has supported the construction of the so-called black route, but said he agreed leaving the decision to Mr Jones' successor was the most appropriate way forward.

"This is undoubtedly going to be the biggest capital spending decision that has been made since devolution 20 years ago, and I think that the importance of it does require, as Rhun ap Iorwerth said in his opening speech, that the decision should be owned by the new first minister," he said.

He added: "We're not talking of immense delay. It's just a couple of weeks before the new first minister is in place. There can surely be no argument for rushing this in the course of the next few hours, in effect, given that we've been waiting for it for such an immense length of time."

Responding to the debate, leader of the house Julie James said Mr Jones was still yet to see the report of the public inquiry into the scheme and the legal advice of Welsh Government officials.

“Clearly this isn't something that's going to take a few hours to read,” she said. “It will take an appropriate length of time for him to be able to go through that – whatever that length of time is.

“So, you can see that the time for that decision is running out. But nevertheless, if this first minister is able to do that, then we think he should do that.

“If he's not able to do it, then he's not able to do it and it will of course go across to the next first minister, whoever she or he is.”

She added it was likely a decision to go ahead with the scheme would be subject to a judicial review, so it was important it was made as legally safe as possible.

“This is not an easy issue,” she said. “The choices before us, as many members have set out, are very hard indeed."

Mark Drakeford, Vaughan Gething and Eluned Morgan are standing to succeed Mr Jones has leader of Welsh Labour and first minister.

Both Mr Gething and Ms Morgan have said they would go-ahead with the scheme - although Ms Morgan has said the new road should be tolled - but Mr Drakeford is thought to be more sceptical.

The winner will be announced on Thursday, December 6, and will take up the role the following Wednesday, December 12.