B roads are numbered routes in Great Britain of lesser importance than A roads. See the article Great Britain road numbering scheme for the rationale behind the numbers allocated.
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3 digits Road From To Notes B400 A4 Fleet Street A40 Holborn Chancery Lane. One way only Northbound B401 A40 High Holborn B402 Long Acre Endell Street. One way only Southbound. Formerly included Bow Street and Wellington Street further south. B402 A400 Charing Cross Road A4200 Kingsway Road Names: Cranbourn Street, Long Acre, Great Queen Street. One-way westbound along Cranbourn Street; one-way eastbound along Long Acre. B403 (defunct) A40 New Oxford Street, London B401 Endell Street, London Now part of the A40 one-way system. B404 A401 Shaftesbury Avenue A400 Charing Cross Road Road Names: Monmouth Street, Upper St Martin's Lane, St Martin's Lane. One-way southbound. Crosses Seven Dials and south end is near St Martin-in-the-Fields, the National Gallery and Trafalgar Square. B405 A4204 Palace Gardens Terrace, near Notting Hill Gate A4204 Kensington Church Street Road Names: Palace Gardens Terrace, Vicarage Gate.
Originally ran along the north side of Trafalgar Square; later upgraded to a loop off the A4. The section along Trafalgar Square is now pedestrianized and the remainder is part of the A4. B406 A5204 Wigmore Street, Marylebone A4201 Regent Street, Mayfair Road Names: Welbeck Street, Henrietta Place, Vere Street, New Bond Street, Conduit Street. One-way southbound except along Conduit Street. B407 (defunct) A4 (now A315) Kensington High Street, London A40 Holland Park Avenue, London Upgraded to Class I status as a portion of the A3220. Southern third is now one-way northbound. B408 A315 King Street, Hammersmith A4020 Shepherd's Bush Road Names: Dalling Road, Paddenswick Road, Askew Road. South part of Dalling Road is one-way southbound. B409 A402 Goldhawk Road, Stamford Brook B490 at Acton Green Road Names: Stamford Brook Road, Bath Road, South Parade B410 A402 Bayswater Road A4205 Praed Street at Paddington station Road Names: Leinster Terrace, Craven Hill, Craven Road B411 A402 Bayswater Road A404 Harrow Road Road names: Queensway, Porchester Road, Lord Hills Bridge. Also includes Inverness Place and Inverness Terrace, for one-way southbound traffic (south part of Queensway is one-way northbound). B412 A219 Shepherd's Bush A4207 Notting Hill To the West of Ladbroke Grove it follows North Pole Road, St Quentin Avenue, St Marks Road and Cambridge Gardens. To the East, through Westbourne Park Road. Crosses Portobello Road. B413 A5 Maida Vale B450 Chamberlayne Road In two parts: Maida Vale to Kilburn Park Road, and Kilburn Park Road to Kensal Green. Via Warwick Avenue Underground station. Road Names: Clifton Road, Clifton Gardens, Warwick Avenue, Formosa Street, Shirland Road, Carlton Vale, Kilburn Lane B414 A5 Maida Vale A404 Harrow Road at Westbourne Green Road Names: Kilburn Park Road, Walterton Road, Fernhead Road B415 A4206 Pembridge Road, near Notting Hill Gate B450 Ladbroke Grove Road Names: Kensington Park Road, Elgin Crescent B416 A4 Wellington Street / A332 roundabout at Slough A413 Amersham Road at Gerrards CrossB417 - B423unused B424 (defunct) Possible typo for the B454. B425 A45 in Sheldon, West Midlands A41 in Solihull B430 A34 at Weston-on-the-Green M40 at Ardley The original route of the A43.B431 - B438unused B439 A46 at Salford Priors A4390 at Stratford-upon-Avon Formerly the A439B440A4146 and A505 roundabout at Leighton BuzzardA4146 and A4147 in Hemel HempsteadDowngraded non-primary section of the A4146, created in 2017 as part of a wider renumbering related to the A5 Dunstable bypass.B441 - B449unused B450 A402 at Holland Park B451 at Kensal Rise Much of this is Ladbroke Grove in Notting Hill and passes close to Portobello Road market. B451 A404 at Kensal Green A5 at Kilburn Via Kensal Green railway station. Road Names: College Road, Mortimer Road, Harvist Road, Brondesbury Road B452 A3002 at Brentford A40 at Perivale Via Brentford railway station, Northfields Underground station and West Ealing railway station. Road Names: Windmill Road, Northfield Avenue, Drayton Green Road, Argyle Road, Teignmouth Gardens
Originally ran from Willesden to Neasden. Upgraded to Class I status as the A4088 in the mid-1920s. B453 A407, Willesden High Road, Willesden A4088, Neasden Junction Passes Neasden Underground Station (Jubilee line) B454 A315 at Isleworth A4127 at Southall Via Syon Lane railway station, and crosses Osterley Park. Road Names: Spur Road, Syon Lane, Windmill Lane. B455 A315 at Brentford A312/A4180 roundabout at Yeading Via South Ealing Underground station and Ealing Broadway railway station. Road Names: Ealing Road, South Ealing Road, Saint Mary's Road, Ealing Green, Bond Street, Ealing High Street, Ealing Broadway, Haven Green, Castlebar Road, Castlebar Hill, Kent Gardens, Scotch Common, Ruislip Road East, Greenford Broadway, Ruislip Road. Haven Green, Ealing Broadway and Ealing High Street are one-way southbound; Bond Street is one-way northbound. B456 A40 Western Avenue A4005 at Alperton Road Name: Alperton Lane B457 (defunct) A4005 at Roxeth A312 at Harrow Now part of a rerouted A4005. B458 (defunct) A404 in Harrow A4005 in Harrow Declassified as it is within Harrow's ring road, and is now one-way westbound. B459 (defunct) A410 in Harrow Wield A410 in Stanmore Declassified after the 1990s. B460 (defunct) A410 in Hatch End A41 in Oxhey Upgraded to Class I status as the A4008 in the 1940s. B461 A4140 at Stanmore A5 at Edgware Whitchurch Lane, past Canons Park station B462 A411 at Bushey Arches A5183 at Radlett B463 (defunct) A404 in Pinner A410 in Pinner Declassified after the 1990s after the rerouting of the A404 north of Pinner. B464 (defunct) A312 north of Harlington A40 (now A4020) in Hillingdon Renumbered to A437; the southernmost section is unclassified. B465 A4020 at Hillingdon A408 at Stockley Park Road Name: West Drayton Road B466 A4020 at Hillingdon A404 at Pinner Via West Ruislip railway station. Road Names: Long Lane, Ickenham High Road, Ickenham Road, Eastcote Road, Eastcote High Road, Cuckoo Hill B467 A4020 at Uxbridge B466 at Ickenham Road Names: Harefield Road, Swakeleys Road B468 (defunct) A404 near Northwood A40 (now A411) in Oxhey Upgraded to Class I status as the A4125. B469 A404 at Northwood A4215 at Northwood Via Northwood Underground station. Road Name: Green Lane B470 A408 at Cowley A4 at Windsor Via Langley railway station. B471 Pangbourne, Berkshire A4074 at Woodcote, Oxfordshire Originally ran from Iver Heath to Denham (now the A412). The northernmost section was later cut in two by the M40 and the old B471, Southlands Road, now goes nowhere. B472 A404 at Northwood Hills B466 at Eastcote Via Northwood Hills Underground station. Road Name: Joel Street First used from Slough to Chalfont St Peter; this was upgraded in the 1920s to a portion of a rerouted A332. Reused along old B473 from Beaconsfield to Amersham when the B473 was rerouted to Hazelmere, but became the B473 (now A355) again in 1935. B473 (defunct) A4 at Slough A413 in Amersham Rerouted to Hazelmere when the A332 replaced the original B472, with the original route to Beaconsfield renumbered to B472. In 1934 the B473 was proposed to be extended south along the B3027, replacing the B474 as a spur to the A332, and rerouted along the B472 to Amersham, with the Beaconsfield-Hazelmere section numbered as a B road (not as B472, however). The extension south was rejected in January 1935 as it would have put the B473 out-of-zone, but the other proposals proceeded as planned and were implemented in April 1935. The Beaconsfield-Hazelmere section was numbered as the B474. Due to an increase of traffic, the B473 was upgraded to Class I status as an extension of the A355 in the 1970s. B474 A40 at Beaconsfield A404 at Hazlemere Former portion of B473. Originally ran from Stoke Poges to Farnham Royal; it was renumbered as a spur of the B473 in 1935. Now part of the B416. B475 (defunct) A4 in Slough Slough railway station Declassified in the 1960s when the A4 was rerouted. B476 (defunct) A4 near Taplow A32 (now A4094) in Wooburn Downgraded because it paralleled the A4094. Now MC61 and C172.B477A4 at Hare HatchA321 at WargraveNarrow with virtually no white line markings in centre of road.B478A4 road at CharvilA4155 (former A32) via Sonning B479 (defunct) A32 in Caversham A423 in Benson Originally ended at the A42 in Streatley, but was rerouted in the 1930s to Benson, with the old route becoming B4526 and B4008 (now B4009). When the A423 was cut in half by the runway at RAF Benson, the B479 was rerouted out of Benson entirely. The section between Benson and the A4130 at Crowmarsh Gifford became a portion of a rerouted A423 in the 1960s with the remainder upgraded to the A4074, which would also replace the A423 after it was rerouted. B480 A4130 Fair Mile, Henley-on-Thames The Plain, Oxford B481 A4155 Caversham B480 just south of Watlington Connects Reading to B4009 at Watlington and hence the M40 2.5miles north of Watlington B482 A4155 Marlow A40 Stokenchurch By way of Lane End, Bolter End and Cadmore End B483 A4020 at Uxbridge A40 at Ickenham Road Name: Park Road B484 (defunct) A416 at High Wycombe railway station A416 at Wycombe Abbey Became a portion of the A404 in 1935. B485 A416 at Chesham A413 at Great Missenden B486 B4635 in Tring B488 in Tring Former portion of the B488 before it was rerouted. Originally ran from Boxmoor to Leighton Buzzard (now A4146, A4012 and B440). B487 Hemel Hempstead A1081 in Harpenden B488 Aston Clinton, Tring A4146 south of Leighton Buzzard, Begins at a grade separated junction east of Aston Clinton. B489 B4009 at Aston Clinton A5/A505 at Dunstable Formerly started on the A41, now crosses the bypassed A41 and starts in Aston Clinton on the B4009. B490 A315 at Chiswick A4020 at Acton Via Chiswick Park Underground station. Road Names: Acton Lane, Beaconsfield Road, Acton Lane, Winchester Street B491 A315 at Chiswick B490 near Acton Via Turnham Green Underground station. Road Names: Turnham Green Terrace, The Avenue, Southfield Road B492 (defunct) A40 in Acton A4000 in Acton Now part of the A4000 one-way system.B493 - B499unused
B4000 to B4099 Road From To NotesB4000A4/A34 at Speen, BerkshireA361 at Highworth, WiltshireVia Lambourn, Ashbury and ShrivenhamB4001A4 at Hungerford, BerkshireA417 north of West ChallowVia LambournB4002 (defunct) New Road, Marlborough The Common, MarlboroughNow part of the A346.B4003A4 near West OvertonA4361 at Avebury Single track throughout length.B4004 (defunct)A361 in Broad HintonA420 in Wootton Bassett Renumbered as a southern extension of the B4041 in 1935. Now unclassified.A48 in Coldra B4237 in Newport The former classification of Ringland Way in Newport. Upgraded to Class I status as the A455 by 1968 and is now part of a rerouted A48 as a portion of the Southern Distributor Road.B4005M4 J16 at Swindon and Wootton BassettA346 road east of ChiseldonVia WroughtonB4006A3102 in West SwindonA4361 north of WroughtonIncomplete orbital route through suburbs of Swindon. Begins west of the centre as part of Great Western Way then orbits north and east, becoming Dorcan Way in the east, and continues through southern suburbs.B4007 (defunct)A415 on Harcourt HillA417 in Harwell Due to its importance, it was renumbered to A4130 in the early 1930s. The eastern end became a portion of a rerouted A423, but later returned to the A4130 after the A423 was rerouted in the 1990s. A small section in Didcot is now the B4016 and the section between Didcot and Harwell is now the B4493.A329 Broad Street, ReadingA4155 Caversham Road, Reading via Queen Victoria Street, Station Road and Tudor Road; declassified by the 1980s.B4008StroudQuedgeleyFormerly part of the A419.