Highways bosses have confirmed that work on three major safety schemes on the A47 has slowed to a virtual standstill due to an environmental campaigner's latest legal challenge.

National Highways officials say the construction work on the projects has been paused, with just 'pre-construction' activities ongoing, until the result of Dr Andrew Boswell's most recent crowd-funded appeal is known.

The former Green councillor has already seen his case thrown out by the High Court and the Court of Appeal, where judges described it as having "no logical basis" and "an air of complete unreality".

However, he has now applied for permission to appeal to the Supreme Court.

Great Yarmouth Mercury: Dr Andrew BoswellDr Andrew Boswell (Image: Dan Grimmer)

National Highways officials have previously said that his ongoing legal challenges have delayed the projects by 20 months and added tens of millions of pounds to the their costs, due to soaring inflation, and Dr Boswell has been under growing political pressure to drop his case.

MPs and councillors have urged him to abandon his "lost cause" which they say is needlessly costing taxpayers money.

Dr Boswell has also been described as a "hypocrite" by George Freeman, whose constituency includes a long stretch of the A47, after it emerged the former UEA academic drove a carbon-emitting petrol car rather than an electric vehicle.

Great Yarmouth Mercury: How the dualled A47 would look between Blofield and North BurlinghamHow the dualled A47 would look between Blofield and North Burlingham (Image: Highways England)Chris Griffin, programme leader for National Highways in the East, said: "The legal challenges have marked a difficult turn of events for those who recognise and support the safety case to upgrade this very busy road, but it remains important that we continue to respect and observe the legal process through to its conclusion."

He said the Supreme Court application meant the government-owned company was restricted to activities, such as archaeological studies and re-routing utilities, such as water and electricity.

Great Yarmouth Mercury: A revamp for Thickthorn roundabout is one of the three A47 schemesA revamp for Thickthorn roundabout is one of the three A47 schemes (Image: Mike Page)

David Thomas, the Conservative prospective parliamentary candidate for Norwich South, said: "There is frustration being felt by thousands of people. People in Norwich and Norfolk have been waiting for this work to be done for years.

"People need these improvements to run their businesses, to get to and from work and to enjoy the county. Whether you agree with Dr Boswell or not, this is not helping anybody for these schemes to be delayed and to become more and more expensive."

Dr Boswell argues that the cumulative environmental impact of the three A47 schemes - to dual sections between Blofield and North Burlingham and Easton to North Tuddenham, and to revamp the Thickthorn roundabout on the edge of Norwich - has not been fully considered and that the government therefore acted unlawfully in granting permission.

He is funding his legal challenges using donations from the public.

It is not known when a decision will be made on whether the Supreme Court will hear the case.