Stop right now! Sorry but £0.5bn is just too high a price to pay for a 12km road improvement scheme in Wiltshire - even if it is around Stonehenge.
English Heritage has been trying to get a scheme to relieve this highly sensitive World Heritage site of its traffic intrusion for decades. Endless options have been considered, all with their pros and all with their cons and all with the ultimate aim of improving the setting of this historically and spiritually important site.
But surely no one in their right mind - least of all professional engineers - can argue that £40M a kilometre for a new road that is at best a poor compromise, represents good sense or value. After all, the public inquiry which ended last February highlighted the fact that even if a tunnel was universally accepted as a valid solution - which it wasn't - the 2.1km tunnel chosen simply wasn't long enough to really make the traffic 'disappear'.
The saving grace for the construction industry is that, thanks to the open-book cost awareness of the Highways Agency's early contractor involvement procurement process, government is at least able to say no to this scheme now.
I certainly believe engineers must continue to take a lead and champion expensive techniques like tunnelling as realistic solutions to infrastructure problems. But as it stands this Stonehenge scheme appears to have become more engineering heart than engineering head.
We are therefore fortunate to know enough, early enough, to be able to say no now.
This is, after all, just the kind of scheme that has wrecked the industry's image in the past.
Had we been dealing with a more traditional procurement approach the contractor would doubtless have bid, won and started the job based on original price estimates. Typically only then would poor ground conditions have been discovered and any new safety measures added.
History suggests that a massive claim would have resulted and transport secretary Alistair Darling, would have had to explain to parliament and the nation why the scheme was going to open late and why the cost had grown by £200M.
OK. The net result would have been a 12km road scheme with a 2.1km twin-bored tunnel delivering a much improved Stonehenge World Heritage Site and attracting thousands more visitors each year.
Balfour Beatty would no doubt have pulled out all the stops to deliver a fi rst rate job and, of course, safeguarded the monument during construction. And I am sure that when completed, despite losing the wonderful, awe-inspiring early morning glimpse of Stonehenge while hammering down the A303 in our cars, the area would have been transformed.
But it would have gone down in history as yet another late, over-budget and compromised scheme rather than a triumph of UK construction delivery.
So while it is always disappointing when so much planning comes to nothing, in its present form this scheme fully deserves to be killed off.
It is not the right scheme to be spending £480M on right now.
Rejoice in the success of modern procurement - nothing got built. We should all learn from and be relieved that the reality of what was ahead was revealed before it was too late.
Antony Oliver is NCE's Editor