The debate in South Wales as to whether the proposed £1bn project to build an M4 relief road will go ahead continues. Proposals were tabled as early as 1991, but the road was postponed two years later and cancelled in 2009 before its latest revival.
Economy Minister Edwina Hart, who is behind the scheme, has claimed it will be "money well spent", but business leaders are urging reassurance that the road will be go ahead even with Hart stepping down as an Assembly Member (AM) in May 2016, which has led to fears among big business, and hope for environmentalists.
A judicial review was rejected earlier this year.
The Welsh Conservatives support the idea of an M4 relief road, which it claims is "essential to ease congestion on the main arterial route through South Wales", but Plaid Cymru and the Welsh Liberal Democrats are opposed to it, as well as a number of Labour AMs.
What are the arguments in favour?
Leighton Jenkins from the Confederation of British Industry Wales told BBC Countryfile Magazine:
"The problem of increased congestion of the M4 around Newport has not gone away. This now has a corrosive impact on investment into South Wales.
"First opened in 1967 as a dual two-lane motorway bypass, this stretch of road utilised the first ever motorway tunnels in the UK which remain in use today. The road was designed and constructed to standards of the day and for much lower traffic flows than are currently experienced. The road lacks continuous hard shoulders, has closely spaced junctions with sub-standard slip road visibility and narrows to a restricted two-lane section through the Brynglas Tunnels.
"Heavy congestion occurs along this stretch and either side of it at peak hours, leading to stop-start conditions that causes unreliable journey times and increased vehicle emissions. The recent spate of incidents along this stretch of road point to the pressure the network is already under. Accidents that lead to severe disruption and delay along the main motorway route to South Wales significantly impact the economy in the short-term and through a loss of confidence in the region’s competitiveness, in the long-term.
"The M4 serves two-thirds of the Welsh population and more than two-thirds of Welsh GDP, and therefore the Welsh government’s proposals are of importance to the whole Welsh economy. Indeed, higher GDP in South Wales will lead to greater government revenue which can be spent across the whole of Wales.
"The reality is that if Wales does not build an M4 relief road it will, increasingly, miss out on hundreds of millions of pounds of future investment. Global and homegrown businesses will, instead, prefer to invest in locations with more modern and reliable infrastructure links. The Prime Minister rightly described the Brynglas Tunnels as a 'foot on the windpipe of the Welsh economy'".
What are the arguments against?
Speaking to BBC Countryfile Magazine, Gareth Clubb from Friends of the Earth Cymru said:
"We’re opposed to the Welsh government’s M4 plans for a number of reasons:
"It will go through or over five Sites of Special Scientific Interest (one of which is a Special Protected Area) and a lot of greenfield land.
"It will cost up to £2 billion, all spent on private transport, when there are any number of active travel and public transport schemes that could benefit from this funding.
"There is no evidence that the proposed development is necessary – other than Welsh government forecasts (notorious for their inaccuracy) predicting catastrophic traffic growth over the next 25 years."
Charities and environmentalists have also pointed out that the plans will mean the demolition of a listed vicarage and a standing stone that is designated a scheduled ancient monument as well as an increase in greenhouse gas emissions. They claim the plans are at odds with the Welsh government's commitment to cut emissions by 3% a year and by 40% by 2020.
There are also fears that it will increase the risk of floods on the Gwent Levels.
Labour backbencher Jenny Rathbone last week said she is "astonished and appalled" by the £20m spent this year (with construction not set to begin until 2018) on consultation and assessing what land would be needed and what environmental measures would be put in place. This is nearly three times what the government last autumn said would be spent in 2015-16.
Rathbone added: "I think nearly all backbenchers are opposed" to the plans, raising fresh doubts about the likelihood of the road being built even if Labour is re-elected in May's Welsh elections. The project may also be at risk if a coalition is formed post-election, with Plaid Cymru and the Welsh Lib Dems, potential coalition partners for Labour or the Conservatives, potentially able to make the road a "red line" issue in coalition negotiations.
A leading campaign group opposed to construction is called Calm, Campaign Against the Levels Motorway, but the debate surrounding the proposal has been anything but. This is likely to continue and possibly even get fiercer still in the run-up to May's Assembly elections.