ONS coding system

Key takeaways

ONS coding system belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect ONS coding system to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of ONS coding system from memory before moving on to harder problems.

Reference excerpt

The ONS coding system was a hierarchical code used in the United Kingdom for tabulating census and other statistical data. ONS refers to the Office for National Statistics. It was replaced by the GSS coding system on 1 January 2011.

Code formulation

Principal authorities The code was constructed top down from a four character code representing a unitary authority or two-tier county and district.

Electoral wards and output areas Local government wards had a two-letter code within their local authority, and census output area an additional four digits within a ward.

The authority and ward codes were recognised by Eurostat as local administrative unit code levels 1 and 2 within the NUTS system.

Civil parishes An overlapping system encoded civil parish areas. Parishes were represented by an additional three digits within their local authority:

List of codes for counties and districts The codes for counties and districts were as follows. Also showing NUTS(3) codes thus: (UKH12)

Greater London These codes became active following local government changes in 1986.

00AA (UKI11) City of London 00AB (UKI21) Barking and Dagenham 00AC (UKI23) Barnet 00AD (UKI21) Bexley 00AE (UKI23) Brent 00AF (UKI22) Bromley 00AG (UKI11) Camden 00AH (UKI22) Croydon 00AJ (UKI23) Ealing 00AK (UKI21) Enfield 00AL (UKI21) Greenwich 00AM (UKI12) Hackney 00AN (UKI11) Hammersmith and Fulham 00AP (UKI12) Haringey 00AQ (UKI23) Harrow 00AR (UKI21) Havering 00AS (UKI23) Hillingdon 00AT (UKI23) Hounslow 00AU (UKI12) Islington 00AW (UKI11) Kensington and Chelsea 00AX (UKI22) Kingston upon Thames 00AY (UKI12) Lambeth 00AZ (UKI12) Lewisham 00BA (UKI22) Merton 00BB (UKI12) Newham 00BC (UKI21) Redbridge 00BD (UKI23) Richmond upon Thames 00BE (UKI12) Southwark 00BF (UKI22) Sutton 00BG (UKI12) Tower Hamlets 00BH (UKI21) Waltham Forest 00BJ (UKI11) Wandsworth 00BK (UKI11) Westminster

Metropolitan counties These codes became active following local government changes in 1986.

Greater Manchester districts 00BL (UKD32) Bolton 00BM (UKD32) Bury 00BN (UKD31) Manchester 00BP (UKD32) Oldham 00BQ (UKD32) Rochdale 00BR (UKD31) Salford 00BS (UKD31) Stockport 00BT (UKD31) Tameside 00BU (UKD31) Trafford 00BW (UKD32) Wigan Merseyside districts 00BX (UKD51) Knowsley 00BY (UKD52) Liverpool 00BZ (UKD51) St Helens 00CA (UKD53) Sefton 00CB (UKD54) Wirral South Yorkshire districts 00CC (UKE31) Barnsley 00CE (UKE31) Doncaster 00CF (UKE31) Rotherham 00CG (UKE32) Sheffield Tyne and Wear districts 00CH (UKC22) Gateshead 00CJ (UKC22) Newcastle-upon-Tyne 00CK (UKC22) North Tyneside 00CL (UKC22) South Tyneside 00CM (UKC23) Sunderland West Midlands districts 00CN (UKG31) Birmingham 00CQ (UKG33) Coventry 00CR (UKG34) Dudley 00CS (UKG34) Sandwell 00CT (UKG32) Solihull 00CU (UKG35) Walsall 00CW (UKG35) Wolverhampton West Yorkshire districts 00CX (UKE41) Bradford 00CY (UKE43) Calderdale 00CZ (UKE43) Kirklees 00DA (UKE42) Leeds 00DB (UKE43) Wakefield

Non-hierarchical codes for Greater London and metropolitan counties 1B Inner London 1C Outer London 2A Greater Manchester 2B Merseyside 2C South Yorkshire 2D Tyne and Wear 2E West Midlands 2F West Yorkshire

Unitary authorities established in the 1990s These codes became active following local government changes the 1990s.

North East England region 00EB (UKC11) Hartlepool 00EC (UKC12) Middlesbrough 00EE (UKC12) Redcar and Cleveland 00EF (UKC11) Stockton-on-Tees 00EH (UKC13) Darlington North West England region 00ET (UKD21) Halton 00EU (UKD21) Warrington 00EX (UKD41) Blackburn with Darwen 00EY (UKD42) Blackpool Yorkshire and the Humber region 00FA (UKE11) Kingston upon Hull 00FB (UKE12) East Riding of Yorkshire 00FC (UKE13) North East Lincolnshire 00FD (UKE13) North Lincolnshire 00FF (UKE21) York East Midlands region 00FK (UKF11) Derby 00FN (UKF21) Leicester 00FP (UKF22) Rutland 00FY (UKF14) Nottingham West Midlands region 00GA (UKG11) Herefordshire 00GF (UKG21) Telford and Wrekin 00GL (UKG23) Stoke-on-Trent South West England region 00HA (UKK12) Bath and North East Somerset 00HB (UKK11) Bristol 00HC (UKK12) North Somerset 00HD (UKK12) South Gloucestershire 00HG (UKK41) Plymouth 00HH (UKK42) Torbay 00HN (UKK21) Bournemouth 00HP (UKK21) Poole 00HX (UKK14) Swindon East of England region 00JA (UKH11) Peterborough 00KA (UKH21) Luton 00KF (UKH31) Southend-on-Sea 00KG (UKH32) Thurrock South East England region 00LC (UKJ41) Medway 00MA (UKJ11) Bracknell Forest 00MB (UKJ11) West Berkshire 00MC (UKJ11) Reading 00MD (UKJ11) Slough 00ME (UKJ11) Windsor and Maidenhead 00MF (UKJ11) Wokingham 00MG (UKJ12) Milton Keynes 00ML (UKJ21) Brighton and Hove 00MR (UKJ31) Portsmouth 00MS (UKJ32) Southampton 00MW (UKJ34) Isle of Wight

Unitary authorities established in 2009 These codes became active following local government changes in 2009.

00KB Bedford 00KC Central Bedfordshire 00EQ Cheshire East 00EW Cheshire West and Chester 00HE Cornwall 00HF Isles of Scilly 00EJ County Durham 00EM Northumberland 00GG Shropshire 00HY Wiltshire

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with ONS coding system

Start with the simplest possible case. Write down what ONS coding system claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to ONS coding system before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about ONS coding system ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of ONS coding system

In research: ONS coding system appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses ONS coding system in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: ONS coding system is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2011 disestablishments in the United Kingdom, Geocodes, Office for National Statistics, so understanding it makes those chapters shorter.
In everyday life: Look for ONS coding system outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study ONS coding system in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what ONS coding system means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain ONS coding system out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is ONS coding system in simple terms?

The ONS coding system was a hierarchical code used in the United Kingdom for tabulating census and other statistical data. ONS refers to the Office for National Statistics.

Why does ONS coding system matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study ONS coding system?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on ONS coding system.