The awe inspired by Stonehenge is equalled only by the tunnel cost

The A303 plan will deny motorists one of Britain’s loveliest views. At £1.6bn, it is money ill spent

If you were to make a list of the country’s greatest vistas what would you include? To my mind, the view of Durham Cathedral from the train heading south takes some beating. Or Lundy Island from the North Devon coast; the Thames from Richmond Hill, the spire of Salisbury Cathedral rising out of the Wiltshire countryside; the Forth Bridges (including the new one).

Yet for me, the greatest of them all is to be seen from the A303, just as you crest the hill after the Amesbury roundabout en route to the West Country. It is, of course, Stonehenge. So the announcement yesterday that the road is (finally) to be sunk into a tunnel to ease congestion will remove one of the world’s most dramatic sights from the passer-by forever. Henceforth, the only way to see the stones will be via the English Heritage visitors’ centre.

From being an integral part of the living landscape for millennia, Stonehenge will become an “experience” reserved principally for tourists – since Brits are only likely to go twice in a lifetime: once as a child and again as a parent.

When I was young and we travelled to Cornwall on holiday from Kent – a pre-bypass journey that could take 12 hours – we parked off the now-closed A344 on the other side of the monument and walked right up to the stones for a picnic. For years that has been prevented by a fence.

As an adult I have driven the A303 countless times and stopped just the once to take our children for the circular walk that is now allowed as the stones become ever more removed from the human contact they were erected to celebrate. I know that this bit of the road, where two lanes become one, is congested because I have often been stuck in the traffic. I know, too, that local people want the tunnel – or at least something to ease the snarl-ups – and resent drive-past gawpers like me telling them they shouldn’t have one. But I’m afraid that this is a special place and that means people will need to put up with a bit of inconvenience to preserve it.

For more than 5,000 years, travellers along the ancient Wessex track called the Harrow Way have passed by and gazed with awe upon Stonehenge. Once the road is in a tunnel then getting to see the monument becomes entirely within the gift of English Heritage. As Karen Bradley, the Culture Secretary, put it: “This investment will help make the visitor experience much more enjoyable.” The idea is to restore “peace and tranquillity” to a landscape that has probably never enjoyed such a pristine state in its history.

Moreover, archaeologists excavating the Neolithic site say digging close to the stones will disturb the burial barrows and could even undermine the monument itself.

The route has been tweaked and will now follow the A303; but the short tunnel that is proposed is the worst of all worlds and has been denounced by Unesco, which lists Stonehenge as a World Heritage Site. A far better alternative would be to construct a bypass to the south of the monument while keeping the existing section of the A303 as a toll road for those who still want to drive past.

But leaving all that aside, why is the tunnel going to cost so much? When it was first mooted 15 years ago, it was estimated at £183 million, only to be abandoned when we needed the money to invade Iraq, even though the economy was booming and the Treasury had just delivered a budget surplus (the last time it did). Now, with the national debt heading towards the £2trillion mark, we apparently have enough cash to build one of the most expensive stretches of road in the land. The current estimate is £1.6 billion – and we all know it will be far more than that.

It has always been a complete mystery to me why infrastructure projects in Britain are so extortionate. HS2 started off at £32.7 billion, which seemed steep enough, but is now projected at £56 billion before a single sleeper has been laid. This is five times what it costs to build high-speed lines in France, Japan and Spain. Even allowing for greater population density in the UK (though Japan is pretty crowded, too) that is an inexplicable cost difference. The Germans and Swedes are building high-speed railways at a fraction of the cost here, partly because so much of HS2 will be tunnels.

Then there is Heathrow’s third runway whose construction costs are estimated at around £19 billion. It cost just £300 million to build Schiphol Airport’s Polderbaan runway, the airport’s fifth. Even the car park at Heathrow will cost £800 million to build. How is this possible? An aircraft carrier is a high-tech, state-of-the-art floating fighting machine; but it is extraordinary that the two new Royal Navy vessels have cost more than £6billion before they are even equipped with fighters, if they are ever are. Or Hinkley Point C. The reactor will cost almost £20 billion to build but the guaranteed strike price for the electricity it produces means consumers will be paying more for their energy while costs from other sources falls. The National Audit Office currently estimates the Hinkley Point subsidy at £60 billion.

Whether or not you think one or all of these projects is needed, the fact remains that infrastructure seems to cost far more here than almost anywhere else (though the Queensferry Bridge recently opened over the Firth of Forth did come in under budget).

Several reasons have been given for this: we have under-invested in infrastructure over the years, so new schemes cost more; a shortage of engineers pushes up prices; land is more expensive than in other countries; planning laws are more onerous; compensation arrangements more generous; and procurement and contract management have been bedevilled with inefficiency for decades. Even so, the costs still seem out of all proportion.

The most recent report from the Infrastructure and Projects Authority shows state spending of around £455billion on a portfolio of 143 major schemes. The body gives traffic-light ratings to each project depending on its likely progress. A red means the successful delivery appears to be unachievable and four schemes have received such a rating. One is the A303 at Stonehenge. That’s red for stop and think again.