A40

A40 is a major trunk road in Great Britain, running for approximately 284 miles from the capital to the western coast of Wales. It connects the metropolis of London with the port of Fishguard, traversing diverse landscapes including the Chiltern Hills, the Cotswolds, and the Brecon Beacons. Historically significant as a primary route to South Wales, it has been superseded for long-distance travel by the M4 motorway and the M50 motorway, but remains a vital artery for local and regional traffic.

Overview

The A40 is one of the original roads classified under the Ministry of Transport's 1922 numbering scheme, forming a key part of the early national network. Its eastern terminus is at the junction with the A501 at Marble Arch in central London, though its continuous trunk route begins further west at Gypsy Corner near Acton. It serves as a primary route through the Home Counties, the South East, and into Wales, officially designated as the London to Fishguard Trunk Road. Key administrative areas it passes through include the Oxfordshire countryside, the historic town of Gloucester, and the rugged terrain of the Welsh Marches.

Route description

From its start in Central London, the road heads west through the suburbs, passing Ealing and Uxbridge before entering the Chiltern Hills Area of Outstanding Natural Beauty near Beaconsfield. It bypasses High Wycombe and ascends the escarpment at Stokenchurch, offering expansive views. The route then descends into the Thames Valley, meeting the A418 before entering Oxford, where it forms part of the city's ring road system. West of Oxford, it crosses the River Thames and heads through the Cotswolds via Witney and Burford, eventually reaching Cheltenham and Gloucester.

Beyond Gloucester, the A40 enters the scenic Wye Valley, passing near the historic market town of Ross-on-Wye and crossing the border into Wales at Monmouth. It then runs through the Vale of Usk, serving Abergavenny before climbing into the Brecon Beacons National Park via the Bwlch pass. After Brecon, it traverses remote moorland to Llandovery and Llandeilo, before meeting the A48 at Carmarthen. The final section runs through Pembrokeshire, passing Haverfordwest and terminating at the ferry port in Fishguard, a departure point for Rosslare Europort in Ireland.

History

The road's lineage follows ancient paths, including sections of the Roman route Iter XII between Calleva Atrebatum (Silchester) and Glevum (Gloucester). In the medieval period, it formed part of the important drovers' road from Wales to the markets of London. Its modern incarnation was solidified with the Special Roads Act 1949 and subsequent trunk road designations. Significant upgrades occurred in the mid-20th century, including the construction of the Western Avenue dual carriageway in London and the High Wycombe bypass. The opening of the M4 motorway in the 1960s and 1970s diverted most long-distance traffic, particularly after the completion of the Severn Bridge in 1966, which provided a faster route to South Wales.

Major junctions

{| class="wikitable" |- ! County ! Location ! mi ! km ! Destinations ! Notes |- | Greater London | Marble Arch | 0.0 | 0.0 | A5 north / A501 / Bayswater Road | Eastern terminus |- | Buckinghamshire | Beaconsfield | 22.5 | 36.2 | M40 – Birmingham, Oxford | Junction 2 |- | Oxfordshire | Wolvercote | 52.0 | 83.7 | A44 – Woodstock, Evesham | Northern Oxford bypass |- | Gloucestershire | Gloucester | 94.0 | 151.3 | A38 / A417 – Tewkesbury, Cirencester | Overlap through city centre |- | Monmouthshire | Raglan | 115.0 | 185.1 | A449 – Newport, Usk | Access to M4 Junction 24 |- | Carmarthenshire | Carmarthen | 230.0 | 370.1 | A48 west / A476 – Swansea, Llanelli | Major interchange |- | Pembrokeshire | Fishguard | 284.0 | 457.0 | A487 – St Davids, Cardigan | Western terminus at harbour |}

Cultural references

The road has been featured in various literary and musical works, symbolizing both escape and connection. It is mentioned in the poetry of John Betjeman, who wrote of the landscape around Stokenchurch. The section through West London is referenced in the The Kinks song "**Dead End Street**". In film, parts of the A40 feature in the 1963 movie "**The Great Escape**", during the motorcycle chase sequence filmed near the Cotswolds. The road's iconic "**Hanger Lane Gyratory System**" in Ealing has been cited as a symbol of complex urban planning in works by J.G. Ballard. Furthermore, the annual London Marathon route crosses the A40 at Gypsy Corner in its early stages.

Category:A roads in Great Britain Category:Transport in London Category:Transport in Wales Category:Roads in Oxfordshire Category:Roads in Gloucestershire