Imperfectly Odd: Hardwick Roundabout

Published on 09 October 2020
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Hardwick Roundabout in Kings Lynn was built ready for a flyover to be added later. But when the bridge arrived in 2003, it wasn't what anyone had expected. Is it Britain's most misunderstood junction?

Imperfectly Odd is our ongoing series of blog posts exploring the most strange, unexpected and fascinating features of the UK's road network. This time we're paying a visit to Norfolk, to a flyover that everybody wanted until it was built, and now nobody seems to be happy with.

What's so odd about Hardwick Roundabout?

You can find this exceptionally large roundabout on the outskirts of King's Lynn, where the A47 bypass finishes. As well as the A47, you'll find the A10 here, ending its journey from London, the A149 heading for the popular north coast of Norfolk, and local roads in to the town centre and an industrial estate. King's Lynn may be small, but Hardwick is very busy indeed.

The roundabout isn't unusual - it's just big, with multiple lanes and lots of traffic lights. The flyover is very strange, though. Approaching from the west, the A47 bypass is a dual carriageway, but it sprouts a single-carriageway flyover, with one lane each way, that crosses the roundabout on a long viaduct. At the far side, instead of free-flowing into the next section of A47, the flyover stops at a roundabout, where curved sliproads lead back to the far side of the roundabout.

A whole lot of flyover for not a lot of free-flowing traffic. Click to enlarge
A whole lot of flyover for not a lot of free-flowing traffic. Click to enlarge

Locals insist the flyover, planned since the 1970s, was supposed to get A47 traffic zooming over the roundabout without stopping. Road enthusiasts complain that there's no point bypassing a roundabout if you're going to install another roundabout and stop everybody anyway. Nobody, it seems, is a fan.

The best laid plans

To understand why everyone is so worked up, let's go back to the beginning.

Opened in 1975, the Kings Lynn Bypass is a short dual carriageway linking the junction of the A47 and A17 in the west to Hardwick Roundabout in the east. It lets through traffic avoid what was previously a single badly congested crossing of the River Great Ouse.

As originally built, the bypass ended at Hardwick, with the roundabout laid out so that it could eventually form a grade-separated junction with a flyover.

Hardwick Roundabout as built in 1975, just six roads and a big roundabout
Hardwick Roundabout as built in 1975, just six roads and a big roundabout

The intended layout was clear from the earthworks that were provided at the time the junction was built. The A47 dual carriageway would extend east towards Swaffham and Norwich, and a flyover would cross Hardwick Roundabout.

The final layout envisaged by the junction's designers in the 1970s, but never built
The final layout envisaged by the junction's designers in the 1970s, but never built

None of that happened. The A47 was never dualled east or west from King's Lynn, and the short bypass remained isolated, but Hardwick Roundabout became ever busier and more congested. Something had to be done.

In the early 2000s, roadbuilding was not fashionable and of little interest to the Government of the day. Further dualling of the A47 had been off the cards for years. Instead, the Highways Agency produced plans for a junction improvement that was considered fairly ambitious for its time: they were going to build a flyover.

Unexpectedly, they cleared away all the embankments that had been built up in the 1970s, built a viaduct spanning the whole junction, and installed a new roundabout at its eastern end. Curved sliproads linked the new roundabout to the old. Hardwick had its flyover, and with it, one of the UK's most distinctive and peculiar junction layouts. It opened in 2003.

The new layout at Hardwick, opened in 2003, which still stands today.
The new layout at Hardwick, opened in 2003, which still stands today.

The new junction is decidedly unconventional and doesn't appear to be a very smart way to add a flyover to a junction. Why speed through traffic across the roundabout only to stop it at another roundabout? It doesn't make sense.

Indeed, since 2003, the Hardwick Roundabout - and its funny little flyover - have come up in conversation dozens of times on the SABRE Forums, where road enthusiasts gather to discuss (and sometimes complain about) British and Irish roads. Every single time, the question has been why the second roundabout was added, and why the new flyover had to come packaged up with this weird junction design.

A bridge too far?

The Highways Agency's decision to build a lengthy viaduct right across the roundabout, held above the flat ground by a series of concrete piers, is a particularly interesting one given that the ground wasn't flat when they arrived to build their flyover.

Back in the early 1970s, when the King's Lynn Bypass was still under construction, the contract included work to provide embankments for flyovers to be provided later at both ends. The embankments at the junction with the A17 to the south-west of the town are still there, one on each side of the roundabout and a mound in the middle that would sit between two bridges.

The same was done at Hardwick, and since the A47 to the east was not on the right line to connect to the future flyover, the new embankment extended some way east of the junction too. You can see it being built in this aerial photo taken at the time.

Earthworks to enable a future flyover, under construction in the early 1970s. Click to enlarge
Earthworks to enable a future flyover, under construction in the early 1970s. Click to enlarge

For the next twenty years, the plan was to finish the junction and extend the dual carriageway. As recently as 1996, in fact, legal orders were published for a scheme to build the flyover exactly as originally planned, even though the dualling project had been dropped. This project was abandoned shortly afterwards too.

Indicative plan from 1996 legal orders for a flyover scheme at Hardwick, making use of those embankments. Click to enlarge
Indicative plan from 1996 legal orders for a flyover scheme at Hardwick, making use of those embankments. Click to enlarge

Between 1996 and 2003, then, the Highways Agency appear to have lost their minds. Instead of completing the junction, they cleared away the earthworks and built a totally different and inexplicably odd design. What on earth were they up to?

Method in the madness

That 1996 plan might just be key to understanding the whole project. With no prospect of the A47 being dualled east towards Swaffham, the huge new dual carriageway flyover and its sliproads would have stopped dead just east of Hardwick, the fast new road reverting to the old at a roundabout providing access to the houses on Constitution Hill. That's not a very good outcome for all that effort and expense.

If the A47 to the east was going to remain a single carriageway road with villages, houses and farm gates by the wayside, there was little point feeding a 70mph dual carriageway into it. The real problem at Hardwick was that the roundabout was overloaded, so when the project returned to the trunk road programme in the early 2000s, it was re-examined from scratch.

The congestion on the roundabout is not caused just by traffic wanting to stay on the A47, which the conventional flyover would serve. Large volumes are trying to get between the other four arms of the roundabout and the bypass. Could the flyover relieve that traffic too?

Well, yes, it could. The strange configuration of the junction means that traffic leaving the bypass is divided, joining the roundabout in two different places depending on where it's going. No journey off the bypass uses more than about a quarter turn of the junction now.

Journeys off the bypass are distributed around the roundabout, avoiding overloading any one part of it.
Journeys off the bypass are distributed around the roundabout, avoiding overloading any one part of it.

In the same way, traffic heading towards the bypass leaves the roundabout in two places, making at most a quarter turn of the junction. Where it passes around the smaller roundabout, it avoids any conflict with the traffic coming off the bypass.

In this way, the flyover doesn't just serve A47-A47 movements; it relieves the roundabout of large volumes of traffic travelling in every direction to and from the bypass. It is a kind of understated genius.

Journeys towards the bypass are distributed in the same way, and with only the smallest points of overlap
Journeys towards the bypass are distributed in the same way, and with only the smallest points of overlap

Today, there is a renewed push for funding to dual the A47 between King's Lynn and Swaffham. No problem: if that happens, a second bridge can still be built alongside the first, and the junction converted to the layout that was originally intended. The current design doesn't prevent that; it simply makes the maximum possible use of the flyover, taking advantage of the fact that the dual carriageway goes no further.

It may even be the case that, if a conventional layout is built, the complaints from locals and road enthusiasts alike that this strange layout makes no sense will be replaced with complaints that the roundabout is overloaded again - because a conventional flyover couldn't possibly provide such complete and complex relief to the roundabout as the present flyover does.

The only remaining question is why the flyover was built as a long viaduct, rather than making use of those embankments, which would have been perfectly good for the current layout and would have meant building two much smaller and cheaper bridge structures.

It's certainly one of the stranger parts of the junction works that were carried out in 2003, but unfortunately no answer to that question has ever been provided. Perhaps the Highways Agency needed the earth for use in another project, or perhaps they just thought a long viaduct would look nicer. Who knows?

While the junction layout might be rather clever, then, in that sense at least the Hardwick Flyover really is Imperfectly Odd.


Bigmac 9 October 2020

This came out quick!

Michael Hardy 9 October 2020

I remember this all being built when I was growing up! If I recall from the local press at the time, the earthworks / mound was removed to make it easier to build the second bridge later on if required - not sure why, but that was the reason given. If you look at the existing flyover it only has streetlights on one side so you can work out where the second flyover was envisaged to go!

The other mystery (to me anyway!) is at the other end of the King’s Lynn Bypass, where it meets the A17. The mound here seems to suggest the idea was to build a flyover to connect the A47 from the east to the A17 to the west. But most traffic turns off to stay on the A47 towards Peterborough and the A1(M). So what was the thought process here - was the A17 going to become more of a major east / west route here?

The A17 is a former trunk route, and is historically the main route between northern England and East Anglia. At the time it would have been the logical way to connect the bypass.

I think most freight traffic has now switched to the longer A1/A47 route (or A1/A14 for those heading to Suffolk) due to the generally unimproved nature of the A17.

Adam Southwell 11 October 2020

Last time I went across Hardwick, the biggest problem wasn't particularly the roundabout - it was more that that the A 149 towards Hunstanton was jammed almost solid. The light phasing allowed a little traffic from King's Lynn to join the A 149, but traffic from the A47 and A10 couldn't get across the box junction.

Anonymous 12 October 2020

Until now, I never knew the arrangement was built in mind for A47(E) to A10(S) to use the flyover and join the roundabout later. Reminds me a bit of Longbridge Island where A46(S) to M40(W) traffic is instructed to cross the motorway over the newer flyover and join the roundabout from the southern end.

Anonymous 14 October 2020

I proposed this for Bad Junctions a few years ago (flying over a roundabout to land on a roundabout will never not be daft), but got shot down on the grounds listed here, that it eases a chunk of the strain on the roundabout by distributing the entries from one side to both.

I still disagree. I lived in Hunstanton (up the A149 from here, probably the most logjammed arm of this roundabout during the summer months) for many years, leaving in '98, and this short-sighted solution was not what was sold; it's tantamount to a big sign in the middle of the roundabout saying "we're not dualling the A47 so shut up about it". Any dualling will now involve building another bridge (when it should have been done properly in the first place), and presumably flattening the eastern roundabout (when it should have been done properly in the first place).

The meme at the time was of traffic getting here from the A47, going all the way round and going straight back home screaming.

There's a persistent rumour that the A10 is going to be rerouted to meet the A47 further east of here, to relieve the strain on West Winch (which is set for housing development). If that was extended to (say) the QE roundabout, or maybe Knight's Hill, or even (at a real stretch) Castle Rising, it could destress the roundabout by leaving it to mainly handle local traffic for South Lynn.

Gavin 17 October 2020

Poor design and one that could have been simplified even further with clover leaf style on the east side of the traffic flows dont cross on that east side. silly design it is as is. needed further work.

Graham Bamber 27 October 2020

I worked on the final design of Hardwick Roundabout in 2000-1. The design with the small roundabout at the east had been fixed some years earlier and would have been based on traffic modelling, keeping within the existing landtake and cost. I'm not sure when or who decided to remove the existing embankment but the material was used to raise the small roundabout thereby reducing the amount of imported fill. It also produced a more aesthetic structure over the large roundabout with better sight lines and improved landscaping.

c2r 31 October 2020

Something that isn't mentioned here, is that in recent years, a minor one-way sliproad that linked Scania Way and Queen Elizabeth Way (A149) was removed, and another roundabout (Jubilee Roundabout) was then added to the A149 just to the north of Hardwick witha cut-through to Scania Way - this allows traffic heading south on the A149 to bypass the Hardwick roundabout when accessing the industrial areas.

Yeah, I never quite understood that sliproad - a one-way road from the Hardwick to the A149 always seemed a bit pointless (it didn't particularly help the roundabout since it was only one turning round, and since that was the more industrial side - I did my Year 10 work experience at a place on Oldmeadow Road - I can't imagine much in the way of heavy machinery was heading from there to Hunstanton...).

Derek Williams 18 December 2020

The KL bypass was opened in 1973 - albeit with a restriction on the river bridge which took some time to finish. I know that because I arrived at the UEA in Norwich in October of that year and distinctly remember driving through the roadworks and seeing the still raw earthworks of the junctions at either end. I was especially annoyed at this, having just driven through Peterborough, which at the time also had incomplete GSJ's

But yes, 1973, not 1975.

Nico Dobben 21 December 2020

As a regular user of the Hardwick Roundabout I decided to dedicate a song to it on my latest album 'Slow You Down'

You can listen to it via the link below

If you don't have Spotify you can hear it at

Glad you posted your link, Nico. That's got you an album sale to me.

Chris R. 15 January 2021

I have this blurry memory from my early childhood in the 1970s. That car journeys to Hunstanton were initially slow, because it was prior to the dual carriageway from Wisbech to King's Lynn. Then the shocking part, just over the Hardwick, the A149 was the same piece of road, more or less, that it is now. However, the big difference was an overtaking lane in the middle - which cars from either direction could take a chance and use! I think I've remembered this correctly, although not sure how far this continued (possibly up towards Sandringham). There are times on that stretch where the road is quite wide, so that must be a clue to the parts where this crazy lane went down the middle. Can you imagine that nowadays, wow!

That three-lane section of the A149 with the middle lane available for overtaking in both directions must have persisted until at least the mid-1990s, as I remember it too, and I didn't move to the area and start using that road occasionally until 1994. There was a similar arrangement on the A299 Thanet Way, east of Herne Bay, which is also no longer there. There still is on on the A40 between Andoversford and Cheltenham. Most of the three lane section is two lanes uphill and one downhill, but there is a stretch at the Cheltenham end where the double white line separating the westbound (downhill) lane from the two eastbound (uphill) lanes disappears, and the centre lane becomes available for both directions.

The three-lane configuration was very common on rural trunk roads from the 1930s through to the 1970s, when they started to disappear. Many old or former trunk roads are still clearly wide enough to carry three lanes, but are now painted down to two.

Half a century ago they were sometimes called "suicide lanes" - the joke being that there was a left side, a right side and a sui-cide.

The overtaking lane was indeed all the way up to Sandrigham (well, Babingley). There's a school of thought that suggests it was at least partially intended as an emergency fast lane for ambulances heading to the Queen Elizabeth Hospital.

Latimer 4 February 2021

Truthfully this junction is a stroke of genius, it makes full use of what's available to it on a budget. And it flows quite well considering it's strangeness. Yeah it could be better, but it's a LOT better than having just the one big roundabout.

Jay 12 February 2021

What I have to wonder is how many people actually use the flyover to travel from the bypass to the A10. Google Maps tells you to go all the way around the roundabout, and I imagine most people would instinctually turn onto a roundabout they know they have to travel around at the first opportunity, even if the signage says otherwise. The design is clever but I think it’s limited by its uniqueness.

Julian O'Dell 18 March 2021

The original embankment was removed and a viaduct used was to provide more flexibility to install future increases in throughput capacity, such as a double roundabout or a hamburger.

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Published9 October 2020

Last updated10 October 2020