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Location Map ( geo)
Cameraicon.png View gallery (41)
From:  Headington, Oxford (SP555074)
To:  Bristol (ST595731)
Via:  Swindon
Distance:  79.5 miles (127.9 km)
Meets:  A40, A4142, B4495, B4150, A4158, B450, A4144, B4044, A34, B4017, A338, A415, B4508, A417, B4000, A419, A4312, A4, B4069, B4158, B4528, A350, B4039, A46, A4175, A4174, B4046, A4017, A431, A4320, A432, A4044
Former Number(s):  A40, A430
Old route now:  A3102, B4069
Primary Destinations
Highway Authorities

Bristol • Oxfordshire • South Gloucestershire • Swindon • Wiltshire

Traditional Counties

Berkshire • Gloucestershire • Oxfordshire • Wiltshire

Route outline (key)
A420 Headington – Botley
A420 Botley – Swindon
A420 Swindon – Chippenham
A420 Chippenham – Bristol


The A420 is a road of varying quality, and more than one section, which skirts around the southern edge of the Cotswolds.

Section 1: Oxford – Swindon

The A420 starts (or ends!) its journey at the Green Road Roundabout (signposted Headington Roundabout, but never called this by locals) near Bury Knowle Park. This is the junction of the A40 from London and Cheltenham and the A4142 Oxford Southern by-pass.

Originally prior to the 1930s Northern Bypass the A40 took the route of the current A420 into the city and out the other side. The road starts its journey through the suburb of Headington and passes Oxford Brookes University; here we make our way down the fairly steep Headington Hill and past South Park.

We now enter St Clements and arrive at the St Clements roundabout, also known as the Magdalen Roundabout, or 'The Plain', once the meeting of the old A423 with our route.

We now cross the long balustraded Magdalen Bridge, famous for the May morning celebrations and into The High. The golden-stoned colleges of Oxford University surround the wide road until we reach Carfax, the main crossroads of Oxford of old. Outside University College there is a traffic restriction, only permitting buses and taxis between 8am and 6pm. Signs encourage others to U-turn, and claim that the restriction is enforced by camera.

This was once the meeting-point of the A40 and the A34; hard to believe if seen now. Before pedestrianisation the route followed Queen Street and New Road, past the Jail and old castle mound before entering Park End Street. The route now travels down St Aldates and past Christchurch College and Cathedral, then right along Thames Street and Oxpens Road (carrying the A4144) before meeting with the original route. We now travel along Botley Road and over the Thames. At the edge of Botley, the A420 turns off the route along the Cumnor Bypass, meeting the A34 as it does so. The original route making its way into Botley, where the original A40 (now B4044) peels off to the right and to Eynsham. The old A420 makes its way up Cumnor Hill and meets the end of the bypass.

Railway bridge

The road from here on is notorious for accidents and has recorded a number of fatalities over the years. Many long running campaigns have been after the dualling of the road all the way to Swindon with no success. The road is fairly wide here, enough for S3 in parts, and is a mishmash of minor improvements and small bypasses. Driving through Tubney Wood and a short dualled section, we arrive at the end of the A338 and its long journey from Bournemouth. We bypass Fyfield and arrive at the newest of improvements on the A420, the Kingston Bagpuize bypass. This short section bypasses a small village with a nasty S-bend junction with the A415. We pass the junction with the B4508, which will eventually rejoin us nearer Swindon. The road is uneventful until we reach the start of the Faringdon bypass. On our right you can see a Folly built on private land. The bypass makes its way downhill where the A417 joins us from the left for a short multiplex. At the next roundabout the A417 leaves us to make its journey on to Cirencester, Gloucester and beyond. We now meet the B4508 again at the start of the Shrivenham and Watchfield bypass. At the end of the bypass the road is crossed by the London – Bristol railway. We pass under it via two single-lane arches. Originally, the now-disused Berkshire and Wiltshire Canal passed under the Swindon-bound arch, road traffic having to use the other arch. We now arrive at the junction with the A419 at Stratton St Margaret. The A420 now loses its number due to many reclassifications over the years. It originally entered Swindon along the now A4312 and via the famous Magic Roundabout.

The section between Oxford and Swindon was previously managed by the Highways Agency as a trunk road, but was detrunked in 2003, following the 1998 review, A New Deal for Trunk Roads in England, the responsibility for this section of the road passing to Oxfordshire Council and Swindon Council.

Section 2: Chippenham – Bristol

A few years after the construction of the M4, the original Swindon to Chippenham route of the A420 was reclassified as the A3102 as far as Lyneham, then as the B4069. Consequently this section now stands in glorious isolation from the rest. It forms a more direct route than the A4 – this is because the A4 originally ended in Bath and was only later extended to Bristol. Indeed the Chippenham-Bristol road enjoyed primary status for many years, but lost it when the M4 was established as a more popular route.

In fact this section was not originally part of the A420 at all. In the 1922 classification it bore the separate number A430 (now in use in Gloucester), but it was then renumbered to create a form of "cannon", with the A420 both entering and leaving Chippenham on the north side of the A4.

A420 through Ford

After leaving the centre of Chippenham, and crossing the new A350 bypass at a roundabout, we pass Sheldon Manor on the left. To the south of the road some rather steep hills separate our route from that of the parallel A4. On this stretch we pass through the villages of Ford and The Shoe, crossing out of Wiltshire and into South Gloucestershire. Here we encounter the large village of Marshfield before coming to a roundabout near Cold Ashton where we cross the A46 – once a rather unsatisfactory set of traffic lights but now greatly improved.

Looking up Tog Hill

In case we're suddenly hit with pangs of hunger, just past here the signs thoughtfully designate a "picnic area" (quite an attractive spot in fact). We pass through Wick, with the Tracey Park Country Club on our left, home to a large private golf course. Then at Bridge Yate the junction with the A4175 heralds the start of Bristol's urban sprawl, though we are not yet within the city boundaries. At a roundabout in Warmley we cross the A4174 Avon Ring Road, continuing into Kingswood and along the High Street. Although Kingswood is to all intents and purposes a suburb of Bristol, it has never been absorbed into the city council area despite numerous local government reorganizations.

At last we cross the city boundary and are joined by the A4017 as we proceed down Two Mile Hill (which also gives its name to the surrounding district). Then, joined by the A431 from Bath from our left, we arrive at the Fountain in St George. We proceed along Church Road with St George Park to our right, coming into a busy row of supermarkets and other shops, and crossing the railway line from Bristol to Cardiff or Birmingham at Lawrence Hill station. Then there's a major traffic landmark - the enormous roundabout where we cross the A4320 Spine Road, a busy dual carriageway connecting the A4 to the M32. This can take some time to negotiate!

A short stretch of dual carriageway leads to a one-way system where we are joined by the A432, and then into Old Market Street – an area notorious for the number of so-called "massage parlours" that have sprung up in recent years, but also boasting some very fine local pubs. The end of the road is at the roundabout at Old Market, where the A4044 former Inner Circuit Road runs beneath the junction. The former course of the A420 ahead from here is now an unclassified road mainly used for access to the Broadmead shopping centre.

External links

Related Pictures
View gallery (41)
The A420 to Faringdon - Geograph - 1671572.jpgA420 through Ford.jpgBristol-centre-1953.jpgA420-Park Road roundabout - Geograph - 60306.jpgA420 Faringdon bypass looking towards Oxford - Geograph - 309829.jpg
Other nearby roads
A4 • A36 • A37 • A38 • A369 • A370 • A403 • A407 (Bristol) • A430 (Chippenham - Bristol) • A431 • A432 • A3024 (Bristol) • A3029 • A3034 (Bristol) • A4017 • A4018 • A4032 • A4044 • A4162 • A4174 • A4175 • A4176 • A4320 • B3119 • B3120 • B3121 (Bristol) • B3122 • B3123 (Bristol) • B3124 • B3125 • B3126 • B3129 • B4045 (Keynsham) • B4046 • B4047 (Gloucestershire) • B4048 • B4049 • B4050 • B4051 • B4052 • B4053 • B4053 (Colston Street, Bristol) • B4054 • B4055 • B4056 • B4057 • B4058 • B4465 • B4466 • B4467 • B4468 • B4469 • E30 • E105 (London - Fishguard) • E116 (Old System) • EuroVelo 1 • EuroVelo 2 • Longest Lane • M4 • M5 • M32 • M49 • NCN4 • NCN41 • Outer Circuit Road • South Bristol Spur • T9 (Britain) • T16 (Britain)
NCN51 • A34 • A40 • A42 (Reading - Birmingham) • A43 • A44 • A423 • A4074 • A4141 (Oxford) • A4142 • A4144 • A4158 • A4165 • A4260 • B480 • B4014 (Oxfordshire) • B4027 • B4150 • B4495 • B4496 • E05 • Longest Lane • M40 • Oxford Ring Road • T10 (Britain) • T13 (Britain) • T42 (Britain) • T47 (Britain) • T114 (Britain)
A400 • A401 • A402 • A403 • A404 • A405 • A406 • A407 • A408 • A409 • A410 • A411 • A412 • A413 • A414 • A415 • A416 • A417 • A418 • A419
A420 • A421 • A422 • A423 • A424 • A425 • A426 • A427 • A428 • A429 • A430 • A431 • A432 • A433 • A434 • A435 • A436 • A437 • A438 • A439
A440 • A441 • A442 • A443 • A444 • A445 • A446 • A447 • A448 • A449 • A450 • A451 • A452 • A453 • A454 • A455 • A456 • A457 • A458 • A459
A460 • A461 • A462 • A463 • A464 • A465 • A466 • A467 • A468 • A469 • A470 • A471 • A472 • A473 • A474 • A475 • A476 • A477 • A478 • A479(W) • A479(E)
A480 • A481 • A482 • A483 • A484 • A485 • A486 • A487 • A488 • A489 • A490 • A491 • A492 • A493 • A494 • A495 • A496 • A497 • A498 • A499
Defunct Itineraries & Motorways: A403 • A404(M) • A405 • A407 • A423(M) • A430 • A437 • A446(M) • A455 • A464 • A475 • A491

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