# CM23

Postcode district covering Bishop's Stortford, New Town and Hockerill, in East Hertfordshire.

CM23 is a postcode district covering Bishop's Stortford, New Town and Hockerill, in East Hertfordshire. Median sale price £437,500 in 2025.

Postcode district. Code CM23. In: [Postcodes](https://openindex.co.uk/postcode) › [CM](https://openindex.co.uk/postcode/cm)

Approximate outline worked out by Open Index from the ONS Postcode Directory: each census output area belongs to the district that holds most of its postcodes. People, homes, recorded crime and broadband add up those output areas. House sales count every sale with an CM23 postcode. [How census figures are added up](https://openindex.co.uk/sources/population)

## Key figures

- **Median sale price: £437,500** (2025). The median price paid for a home in CM23 was £437,500 in 2025. Joint 471st most expensive of 2,235. Source: Worked out by Open Index from HM Land Registry Price Paid Data. Published 28 September 2026. https://openindex.co.uk/postcode/cm23#f-house-sales-median-price
- **Population: 44,136** (2021). CM23 had 44,136 usual residents at the census (ONS Census 2021). 332nd most populated of 2,756. Source: Census 2021, England and Wales and Scotland's Census 2022 and Census 2021, Northern Ireland, 2021. Published 21 July 2026. https://openindex.co.uk/postcode/cm23#f-population
- **People in radon Affected Area squares: 61%** (2022). About 61% of people in CM23 live in a 1 km square that the radon atlas marks as a radon Affected Area. UK 44%. Source: Worked out by Open Index from the UKHSA and BGS radon atlas and census output areas. Published 1 December 2022. https://openindex.co.uk/postcode/cm23#f-radon-affected-share
- **Gigabit broadband coverage: 87.7%** (January 2026). In CM23, 87.7% of homes and businesses could get gigabit-capable broadband in January 2026 (Ofcom). UK 87.8%. Source: Connected Nations (Ofcom), January 2026. Published 13 May 2026. https://openindex.co.uk/postcode/cm23#f-gigabit-coverage

## On the map

- [Radon Affected Area by postcode district](https://openindex.co.uk/map/radon-affected-areas?place=CM23) (Worked out by Open Index · 2022): About 61% of people in CM23 live in a 1 km square that the radon atlas marks as a radon Affected Area.
- [Sales per year by postcode district](https://openindex.co.uk/map/house-sales-per-year?place=CM23) (Worked out by Open Index · 2025): 804 homes were sold in CM23 in 2025.
- [Crime and ASB by postcode district](https://openindex.co.uk/map/recorded-crime?place=CM23) (Police recorded crime and outcomes (data.police.uk) · August 2026): Crime and anti-social behaviour for CM23.
- [Population by postcode district](https://openindex.co.uk/map/population?place=CM23) (Census 2021, England and Wales): CM23 had 44,136 usual residents at the census.

## How CM23 compares

Each postcode district against every other postcode district the measure covers.

| Measure | CM23 | Rank | Compared with |
| --- | --- | --- | --- |
| Median sale price | £437,500 | 13th most expensive | 25 postcode districts, CM · 2025 |
| Population | 44,136 | 5th most populated | 27 postcode districts, CM · 2021 |
| People in radon Affected Area squares | 61% | 2nd most people in radon Affected Areas | 27 postcode districts, CM · 2022 |
| Gigabit broadband coverage | 87.7% | joint 12th lowest | 27 postcode districts, CM · Jan 2026 |

## Is CM23 safe? What police records show

In the 12 months to August 2026, police recorded crimes and anti-social behaviour in CM23 at a rate of 79.4 per 1,000 people.
That compares with 77.3 per 1,000 people across the CM postcode area.
In August 2026 alone, 365 cases of crime and anti-social behaviour were recorded in CM23.
In the 12 months to August 2026, the most common types were violence and sexual offences (1,255), anti-social behaviour (908) and other crime (549).
A year earlier, the recorded crime rate in CM23 was 71.0 per 1,000 people.
Worked out by Open Index from police.uk crime records and ONS and NISRA population estimates.
Rates are per resident, so places that many people work in or visit, such as Westminster, the City of London and other city centres, have far higher rates than their residents alone would suggest.

## Deprivation in CM23, neighbourhood by neighbourhood

- Deprivation is ranked by neighbourhood, so CM23 has no single figure. Of its 27 neighbourhoods with a rank:
- Decile 3: 1 neighbourhood
- Decile 6: 1 neighbourhood
- Decile 7: 4 neighbourhoods
- Decile 8: 2 neighbourhoods
- Decile 9: 4 neighbourhoods
- Decile 10 (England’s least deprived 10%): 15 neighbourhoods

Source: English Indices of Deprivation 2025. Decile 1 is the most deprived tenth of neighbourhoods in England.

## Neighbourhoods in CM23

| Area | People (census) | Recorded crime per 1,000 | Deprivation decile | Gigabit broadband |
| --- | --- | --- | --- | --- |
| [East Hertfordshire 003A](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023452) | 1,303 | 19.5 per 1,000 | 10 | 100.0% |
| [East Hertfordshire 003B](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023453) | 2,074 | 56.4 per 1,000 | 10 | 94.3% |
| [East Hertfordshire 003C](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023454) | 2,227 | 73.5 per 1,000 | 10 | 98.2% |
| [East Hertfordshire 003D](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023455) | 1,363 | 25.5 per 1,000 | 10 | 90.1% |
| [East Hertfordshire 004A](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023449) | 1,819 | 139.3 per 1,000 | 10 | 72.8% |
| [East Hertfordshire 004C](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023451) | 2,307 | 45.7 per 1,000 | 10 | 86.9% |
| [East Hertfordshire 004D](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01035590) | 1,610 | 124.6 per 1,000 | 7 | 97.2% |
| [East Hertfordshire 004E](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01035591) | 1,131 | 416.6 per 1,000 | 6 | 41.2% |
| [East Hertfordshire 005A](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023438) | 1,527 | 60.1 per 1,000 | 9 | 92.0% |
| [East Hertfordshire 005B](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023439) | 1,417 | 58.9 per 1,000 | 8 | 97.4% |
| [East Hertfordshire 005C](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023440) | 1,737 | 36.6 per 1,000 | 10 | 77.5% |
| [East Hertfordshire 005D](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023441) | 1,523 | 65.6 per 1,000 | 9 | 86.7% |
| [East Hertfordshire 005E](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023442) | 2,256 | 68.7 per 1,000 | 9 | 84.6% |
| [East Hertfordshire 007A](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023443) | 1,403 | 17.4 per 1,000 | 10 | 84.9% |
| [East Hertfordshire 007B](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023444) | 1,904 | 60.0 per 1,000 | 10 | 92.7% |
| [East Hertfordshire 007C](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023445) | 1,735 | 89.3 per 1,000 | 7 | 91.7% |
| [East Hertfordshire 007E](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023447) | 1,327 | 89.3 per 1,000 | 3 | 96.5% |
| [East Hertfordshire 007F](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023448) | 1,472 | 119.3 per 1,000 | 10 | 91.9% |
| [East Hertfordshire 007G](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01035594) | 1,451 | 208.2 per 1,000 | 8 | 88.6% |
| [East Hertfordshire 007H](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01035595) | 1,081 | 182.3 per 1,000 | 7 | 91.5% |
| [East Hertfordshire 008A](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023456) | 1,336 | 12.3 per 1,000 | 10 | 91.0% |
| [East Hertfordshire 008B](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023457) | 1,472 | 25.2 per 1,000 | 10 | 95.3% |
| [East Hertfordshire 008C](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023458) | 1,380 | 35.6 per 1,000 | 9 | 95.8% |
| [East Hertfordshire 008D](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023459) | 1,293 | 59.4 per 1,000 | 10 | 89.1% |
| [East Hertfordshire 008E](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023460) | 1,545 | 79.2 per 1,000 | 10 | 91.6% |
| [East Hertfordshire 008F](https://openindex.co.uk/east-hertfordshire/neighbourhood/e01023461) | 1,557 | 28.0 per 1,000 | 10 | 100.0% |
| [Uttlesford 005G](https://openindex.co.uk/uttlesford/neighbourhood/e01022089) | 1,612 | 21.6 per 1,000 | 7 | 77.7% |

## Your MP

- [Hertford and Stortford](https://openindex.co.uk/constituency/hertford-and-stortford): Josh Dean (Labour), MP since July 2024. 92% of the people here.
- [North West Essex](https://openindex.co.uk/constituency/north-west-essex): Mrs Kemi Badenoch (Conservative), MP since July 2024. 8.2% of the people here.
- [Harlow](https://openindex.co.uk/constituency/harlow): Chris Vince (Labour (Co-op)), MP since July 2024. 0.2% of the people here.
- [North East Hertfordshire](https://openindex.co.uk/constituency/north-east-hertfordshire): Chris Hinchliff (Labour), MP since July 2024. 0.1% of the people here.

As of 18 October 2026. Contains Parliamentary information licensed under the Open Parliament Licence v3.0. Source: UK Parliament, Members API.

## Middle areas in CM23

[Bishop's Stortford Central](https://openindex.co.uk/east-hertfordshire/bishops-stortford-central), [Bishop's Stortford East](https://openindex.co.uk/east-hertfordshire/bishops-stortford-east), [Bishop's Stortford North](https://openindex.co.uk/east-hertfordshire/bishops-stortford-north), [Bishop's Stortford South](https://openindex.co.uk/east-hertfordshire/bishops-stortford-south), [Bishop's Stortford West & Braughing](https://openindex.co.uk/east-hertfordshire/bishops-stortford-west-and-braughing)

## Postcode sectors in CM23

[CM23 0 (45 postcodes)](https://openindex.co.uk/postcode/cm23-0), [CM23 1 (137 postcodes)](https://openindex.co.uk/postcode/cm23-1), [CM23 2 (300 postcodes)](https://openindex.co.uk/postcode/cm23-2), [CM23 3 (265 postcodes)](https://openindex.co.uk/postcode/cm23-3), [CM23 4 (231 postcodes)](https://openindex.co.uk/postcode/cm23-4), [CM23 5 (203 postcodes)](https://openindex.co.uk/postcode/cm23-5), [CM23 9 (19 postcodes)](https://openindex.co.uk/postcode/cm23-9)

## Council

[East Hertfordshire](https://openindex.co.uk/east-hertfordshire)

## Towns in CM23

[Bishop's Stortford](https://openindex.co.uk/town/bishops-stortford)

## Postcode districts next to CM23

[CB11](https://openindex.co.uk/postcode/cb11), [CM21](https://openindex.co.uk/postcode/cm21), [CM22](https://openindex.co.uk/postcode/cm22), [CM24](https://openindex.co.uk/postcode/cm24), [SG9](https://openindex.co.uk/postcode/sg9), [SG11](https://openindex.co.uk/postcode/sg11)

## Nearest rail stations

[Bishops Stortford (1.5 km from the middle)](https://openindex.co.uk/map/rail-stations?around=0.1649,51.8667), [Stansted Mountfitchet (3.7 km from the middle)](https://openindex.co.uk/map/rail-stations?around=0.1998,51.9014)

## More in the CM postcode area

[All CM postcode districts](https://openindex.co.uk/postcode/cm), [Every UK postcode area](https://openindex.co.uk/postcode)

## CM23 in brief

CM23 is a postcode district covering Bishop's Stortford, New Town and Hockerill, in East Hertfordshire.
About 47,349 people lived in CM23 in mid-2024 (worked out by Open Index from ONS small-area estimates); the median price paid for a home was £437,500 in 2025 across 804 sales (HM Land Registry) and police recorded crimes and anti-social behaviour at a rate of 79.4 per 1,000 people in the 12 months to August 2026 (police.uk).
The median price paid for a home in CM23 was £437,500 in 2025.
CM23 had 44,136 usual residents at the census.
About 61% of people in CM23 live in a 1 km square that the radon atlas marks as a radon Affected Area.
In CM23, 87.7% of homes and businesses could get gigabit-capable broadband in January 2026.

## About

- Type: Postcode district
- Code: CM23
- Postcode area: [CM](https://openindex.co.uk/postcode/cm)
- Constituency: [Hertford and Stortford †](https://openindex.co.uk/constituency/hertford-and-stortford)
- Council: [East Hertfordshire †](https://openindex.co.uk/east-hertfordshire)
- Area: 50.03 km²
- People, mid-2024: 47,349*
- Neighbourhoods: 27
- Output areas: 134

* People: worked out by Open Index from neighbourhood estimates, shared out by where people lived at the census (by area in Northern Ireland). This area's edges do not follow neighbourhood edges, so the figure is close but not exact.
† Best fit: the constituency, council, region and nation this postcode district mostly lies in. Its edges do not follow theirs.

## Next door

[CM22](https://openindex.co.uk/postcode/cm22), [CM21](https://openindex.co.uk/postcode/cm21), [CM24](https://openindex.co.uk/postcode/cm24), [SG11](https://openindex.co.uk/postcode/sg11), [CB11](https://openindex.co.uk/postcode/cb11), [SG9](https://openindex.co.uk/postcode/sg9)

## Latest updates for CM23

- August 2026 house prices published: HM Land Registry and partners · Oct 2026.
- September 2026 rent published: ONS private rents · Oct 2026.
- Dental practices updated: NHS England · Oct 2026.
- Schools updated: Ofsted · Oct 2026.

The same figures as JSON: https://openindex.co.uk/v1/places/CM23

## How to cite

Source: Open Index, openindex.co.uk. Link to this page, https://openindex.co.uk/postcode/cm23, or to one figure with its anchor, https://openindex.co.uk/postcode/cm23#f-house-sales-median-price.

Open Index's own text and the figures it works out are licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source data keeps its publishers' licences, named with each figure. Give each figure's period and source with it.

Snapshot 2026.10.9. The HTML page: https://openindex.co.uk/postcode/cm23