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.
Zone 5 (3 digits) Road From To Notes B500 A40 at Holborn Circus A1 at Barbican tube station Charterhouse Street and Long Lane around Smithfield Market B501 A401 at Islington B500 Charterhouse Street, Smithfield Market St John Street, except for the section north of Rosebery Avenue which is part of the A401 B502 A4200 at Russell Square B144 Bath Street in Finsbury This road is split into two parts by the A201 and A401 at Mount Pleasant B503 (defunct) A401 at Mount Pleasant A501 at Kings Cross Now part of the A201. B504 A5202 at St Pancras B502 at Bloomsbury Northern section passes St Pancras International on the west side and is southbound-only for through traffic. B505 (defunct) A40 at Oxford Circus A400 at Camden Upgraded to a portion of the A4201, but that was later rerouted onto the parallel Portland Place instead of Great Portland Street, returning it to Class II status, but it became the B506 instead of the B505. The section along Mortimer Street is now part of the A5204. B506 Marylebone Road Russell Square Great Portland Street and Mortimer Street east of Regent Street. Originally ran between the A5 and A400 (paralleling the A40), with a multiplex with the B505 at the western end of Mortimer Street. The B505 was upgraded to the A4201, and the section of B506 west of the B505 was also upgraded, probably to the A5204. The B506 was extended along the old route of the A4201 when it was rerouted along Portland Place. The remainder of the original B506 is now part of an extended A5204. The original route was also extended further east and when that became the A4201, the extension remained, dividing the route into two sections. B507 A501 at Marylebone B510 at Kilburn Lisson Grove and includes the famous Abbey Road B508 (defunct) A5 in Maida Vale B505 (now A4201) near Camden Upgraded to the A5205, likely early on because the number fits into the original system (four-digit A roads in central London were numbered Ax2xx). B509 A502 at Chalk Farm A5 at Kilburn Adelaide Road and Belsize Road, passes through Swiss Cottage B510 A41 at Child's Hill (Fortune Green) A5 at Kilburn Along Fortune Green Road and West End Lane through West Hampstead. Terminates at Quex Road while Abbey Road is the B507 B511 A41 at Swiss Cottage A502 at Hampstead tube station Fitzjohns Avenue and some of Heath Street B512 A400 at Mornington Crescent tube station A5202 at St Pancras Hospital Crowndale Road B513 (defunct) A501 near Kings Cross station B519 Waterlow Park Originally ended at the B514. The sections along Dartmouth Park Hill and Randell's Road are unclassified and the remainder is part of the A5200. B514 A5200 York Way, King's Cross Caledonian Road, Barnsbury Copenhagen Street B515 A1 at Holloway A1 at Islington Liverpool Road. Passes through residential Islington. As this road is an alternative to the A1, it attracts rat-runners, therefore a 20 mph speed limit has been introduced throughout with traffic calming (speed humps) to enforce it. B516 (defunct) A503 in Holloway, London A5203 in Holloway, London Now part of the A503 one-way system. B517 A502 in Chalk Farm B518 Hampstead at the one-way system This is an alternative route to Hampstead to the A502 that passes through Malden Road. B518 A502 at Rosslyn Hill, Hampstead A400 at Kentish Town station Route runs along Pond Street, passing Gospel Oak station and the Royal Free Hospital, and runs close to the southern border of Hampstead Heath. B519 A502 at Jack Straw's Castle, Hampstead A1/A400 in Archway Includes a spur along North Road to the A1. B520 A5 in Kilburn, London B510 in Kilburn, London Iverson Road B521 A40 at Holborn Circus A5201 Clerkenwell Road Hatton Garden B522 (defunct) A40 in St Giles A400 in Euston Much of route now part of the southbound route of the A400; the section along North Gower Street is now unclassified and its northern end closed to traffic. B523 (defunct) A5024 at Portman Square A41 Park Road near Regents Park Now part of the northbound route of the A41. B524 A41 Baker Street A40 Oxford Street Paddington Street, Paddington Street Gardens, Marylebone High Street, Thayer Street, James Street B525 Swiss Cottage Regent's Park Avenue Road B526 A422 at Newport Pagnell A45/A508 junction, Northampton Parallel to M1 motorway (formerly part of the A50)B527unused B528 (defunct) A5 in Hockliffe A418 in Woburn Originally part of the A506 (later A50). Now part of the A4012. B529 (defunct) B5219 in Moss Side A560 at Wythenshawe Shown as B5290 on a 1932 map, but is likely a typo. Upgraded to the A5103 by 1934. B530 Fancott, Bedfordshire A6/A421, Bedford The only direct link between Flitwick/Ampthill and Bedford. Section between Flitwick and the M1 Junction 12 forms part of the A5120 B531 A5134 at Kempston, Bedfordshire A5141 in Bedford town centre Straight for its entire lengthB532 - B539unused B540 B519 Highgate Village, North London A103 Crouch End Heads along Hornsey Lane, over the A1 at the Archway BridgeB541 - B549unused B550 B519 Highgate Village, North London A1000 Whetstone, London Southwood Lane, Muswell Hill Road, Muswell Hill Broadway, Colney Hatch Lane and Friern Barnet Lane B551 A41 at Hendon A502 at Brent Green, Hendon Along Queens Road B552 A504 at Hendon A411 at Arkley Runs through North Hendon and Mill Hill Village, runs along the A5109 for a short while at Highwood Hill, then up Hendon Wood Lane to Arkley. B553 (defunct) A5 in Edgware A1 in Whetstone Upgraded to the A5109, likely in the 1940s. B554 (defunct) B553 (now A5109) at Highwood Hill A411 at Barnet Gate Renumbered as a northern extension of the B552. B555 (defunct) A5 north of Radlett A414 in Hatfield Section between Colney Heath and Hatfield became the A5092 (later A555, now A1) in 1926 when the Barnet bypass opened. Renumbered to B556 in 1935, probably to avoid confusion with the Barnet bypass which was given the A555 number. B556 A1000 and A111 at Potters Bar A5183 north of Radlett Previously ran between Dunstable and Ampthill (partially now A5120). B557 (defunct) A5 near Fenny Stratford A6 in Bedford Section north of the M1 became the A5140 (later A421, now C94), the section along the Bedford bypass became a portion of the B531 and the section south of the M1 was declassified with the growth of nearby Milton Keynes. B558 (defunct) A506 (later A50) in Woburn Sands B557 in Apsley Hill Declassified sometime after the 1970s. B559 (defunct) B557 in Church End A418 in Husborne Crawley Was a portion of the A507; now declassified. B560 A422 at Stagsden, Bedfordshire A5134 at Kempston, Bedfordshire B561 (defunct) B557 in Kempston A428 in Bromham Except for the easternmost end, it was renumbered B562 (later A5134) in 1935. The easternmost end (which was never upgraded to an A road) is now part of the B531. After this section of the A5134 was downgraded in 2009 due to construction of the A418 Bedford western bypass, the route west to Kempston Church End became the B560 and the remainder declassified. B563 (defunct) B557 in Bedford A6 in Bedford Upgraded to Class I status as the A5141. B564 (defunct) B563 in Bedford A6 in Bedford Declassified; the eastern half is now pedestrianized. B565 A509 at Olney, Buckinghamshire A428 at Cold Brayfield, Buckinghamshire B566 (defunct) A43 in Northampton A43 in Northampton Became a portion of the B567, forming half a ring road. Now part of the A5123 relief road. B567 (defunct) A428 in Northampton A43 in Northampton The section along Spencer Bridge Road and Grafton Street is now part of the A428 and the remainder is now the A5123. B568 Welford Road, Leicester London Road, Leicester Originally ran between Northampton and Leicester (now A5199 and A5095). B569 Old A6 at Rushden A509 at Wollaston near Wellingborough B570 B569 near Irchester A509 near Little Irchester B571 A5128 in Wellingborough A6 Irthlingborough bypass Originally ended at the A5193 (formerly A45), but was extended west to its current terminus in the mid-1920s. B572 A5128 in Wellingborough Wellingborough railway station Originally began at the A510. B573 (defunct) A45 (now A5128) Northampton Road, Wellingborough A510 (now A5128) Finedon Road, Wellingborough Renumbered B5386 for unknown reasons, but is now unclassified. B574 A509 in Great Harrowden A509 at Hill Top Loop serving Little Harrowden B575 A6003 in Kettering Kettering railway station B576 A6 Desborough bypass A14 J3 in Rothwell Much of route formerly A6. B577 (defunct) A5 at High Cross B411 (later A427) in Lutterworth Declassified sometime after the 1990s. B578 B4669 east of Hinckley A5 near Smockington B579 A505/A6 spur in Luton B5120 in Toddington Originally ran from Hinckley to Sapcote (now B590 and B4669). B580 (defunct) A447 (now B4667) in Hinckley A47 (now B590) in Hinckley Declassified after Hinckley was bypassed. B581 A47 Earl Shilton bypass near Elmesthorpe A426 at Dunton Bassett Originally classified as "Barwell Fields - Earl Shilton", connecting the A447 and A47 through Barwell to the north of Hinckley, and was extended to Dunton Bassett in the mid-1920s. By 1932, the original section was upgraded to Class I status as the A5096, but was downgraded again in the 1960s, likely returning to the B581. The section west of the A47 Earl Shilton bypass (including the entire original section) was declassified after the bypass was built and is now a dead end after Elmsthrope Lane was split by the bypass. B582 A447 at Belcher's Bar A6030 in Stoneygate Originally started further south on the A447, at Osbaston Toll Gate and ran east to meet the B585 on the edge of Newbold Verdon (this is now unclassified) and originally continued to the A47 in Thurnby (a portion of this is now the B568). B583 (defunct) A46 (now A5460) in Leicester A6 in Leicester Upgraded to Class I status in the 1960s as the A5125 (later A46). Declassified after the A46 was rerouted, but the northernmost section is now part of the A6 and the section north of the A50 is now the B5327. B584 (defunct) A444/A5 in Caldecote A483 near Measham Section south of Twycross became a northern extension of the A444 and the northern section became the B4116. B585 A447 near Cadeby, Leicestershire A511 between Coalville and M1, Leicestershire Rerouted; formerly via Coalville to A512 at Thringstone; this section now classified unnumbered B586 A511 in Midway A514 in Swadlincote Route south of Swadlincote to Ibstock now unclassified. B587 A514 near Stanton by Bridge, Derbyshire A511 east of Ashby-de-la-Zouch, Leicestershire Rerouted; formerly, via Whitwick to A50 at Markfield; this section now classified unnumbered B588 (defunct) A6 at Hathern, Leicestershire A512 south of Shepshed, Leicestershire Declassified sometime after the 1990s. B589 A6 in Loughborough A60 in Loughborough Originally ran along Broad Street from the A512 to the A6, but this was declassified around 1980. The current B589 follows the former A6004 on the wrong side of the A6, putting the B589 out-of-zone. B590 Rugby Road in Hinckley Rugby Road in Hinckley Inner town loop around Hinckley; one section is former B5402. B591 A512 south of Shepshed, Leicestershire A50 west of M1 Junction 22, Leicestershire Rerouted; incorporates sections of former B5330 and B5350. Formerly: east (from near Copt Oak) to A6 at Quorn, Leicestershire, and west from A50 to Ibstock and beyond; both these sections now unnumbered classified roads.B592 - B599unused
B5000 to B5099