Salisbury MP John Glen has put his weight behind the government's A303 road plan which was formally being announced today.

As the Prime Minister David Cameron and Deputy PM Nick Clegg prepared to travel to Stonehenge for today's announcement, the MP said the plan is hugely welcome.

He said: "For decades, the A303 has been the thorn in the side of the south west’s transport infrastructure. The notorious delays at Stonehenge have damaged the south west region’s economic potential. British Chambers of Commerce have estimated that unblocking this route will initially catalyse £1.1 billion of growth, and will bring some £74bn of wider economic benefits over the next sixty years.

"As importantly, this announcement is positive news for Britain’s heritage and tourism industries - Stonehenge is one of the world’s most iconic World Heritage sites. For too long Stonehenge has been blighted by traffic and its landscape marred by poorly sited roads immediately adjacent to the Stones themselves. By investing in what will be Britain's longest land tunnel we will finally do justice to such a precious international site by restoring the natural beauty of the historic landscape surrounding the Stones.

"For many locally this news will be enthusiastically welcomed after years of traffic jams, delays and chaos caused by numerous road traffic accidents as well as the disruption of lorries thundering through Winterbourne Stoke. I pay tribute to Cllr Ian West, my predecessor Robert Key and local campaigners who have worked on this campaign over many years."

John Glen said the announcement will mark the start of a process of detailed design work and an application for planning approval

"There are some outstanding concerns that will need to be carefully addressed: (especially the impact on the archaeology of the World Heritage Site; on continued access to Stonehenge for locals - especially from Amesbury; on water flows and on traffic arrangements nearby). We must ensure that this significant investment of taxpayer’s money is spent wisely and that the detailed work undertaken on the previous suggested schemes is not wasted.

"However, as I said in my Westminster Hall debate on 4th March 2014, it seems quite clear that a tunnel is the only deliverable option. Over 50 alternatives have been explored in the past, and all of them have been found to be undeliverable. The determination of English Heritage and the National Trust to reach a consensus on a tunnel has been decisive; the proposed solution has in principle support from both parties, in addition to the Council of British Archaeologists, Wiltshire Council and the CBI.

"I recognise that there are some who will be sceptical that this scheme will be delivered given plans for a tunnel under Stonehenge are as almost as old as the stones themselves. I will be working hard in the coming months to ensure that the detailed plans satisfy the remaining unanswered questions so that this challenging infrastructure project will be delivered for my constituents and the wider heritage and economic interests of the country."