The local memory tag, or area code ER is for cars first registered in Chelmsford (E is the official local mnemonic for Essex. R is the local office identifier for Chelmsford). Listed below are the 49 age identifier number plate prefix combinations currently in use that start with ER. New prefixes are added in March and September each year. The first plate in the present number plate format was 51 issued on 1 September 2001.
The latest released plate prefix is ER75 first issued 1 September 2025. The next number plate prefix to be released will be ER27 on 1 March 2027.
| Year | Prefix | Issued Date Range |
|---|---|---|
| 2001 | ER51 | 1 September 2001 - 28 February 2002 1 September 01 - 28 February 02 |
| 2002 | ER02 | 1 March 2002 - 31 August 2002 1 March 02 - 31 August 02 |
| ER52 | 1 September 2002 - 28 February 2003 1 September 02 - 28 February 03 | |
| 2003 | ER03 | 1 March 2003 - 31 August 2003 1 March 03 - 31 August 03 |
| ER53 | 1 September 2003 - 29 February 2004 1 September 03 - 29 February 04 | |
| 2004 | ER04 | 1 March 2004 - 31 August 2004 1 March 04 - 31 August 04 |
| ER54 | 1 September 2004 - 28 February 2005 1 September 04 - 28 February 05 | |
| 2005 | ER05 | 1 March 2005 - 31 August 2005 1 March 05 - 31 August 05 |
| ER55 | 1 September 2005 - 28 February 2006 1 September 05 - 28 February 06 | |
| 2006 | ER06 | 1 March 2006 - 31 August 2006 1 March 06 - 31 August 06 |
| ER56 | 1 September 2006 - 28 February 2007 1 September 06 - 28 February 07 | |
| 2007 | ER07 | 1 March 2007 - 31 August 2007 1 March 07 - 31 August 07 |
| ER57 | 1 September 2007 - 29 February 2008 1 September 07 - 29 February 08 | |
| 2008 | ER08 | 1 March 2008 - 31 August 2008 1 March 08 - 31 August 08 |
| ER58 | 1 September 2008 - 28 February 2009 1 September 08 - 28 February 09 | |
| 2009 | ER09 | 1 March 2009 - 31 August 2009 1 March 09 - 31 August 09 |
| ER59 | 1 September 2009 - 28 February 2010 1 September 09 - 28 February 10 | |
| 2010 | ER10 | 1 March 2010 - 31 August 2010 1 March 10 - 31 August 10 |
| ER60 | 1 September 2010 - 28 February 2011 1 September 10 - 28 February 11 | |
| 2011 | ER11 | 1 March 2011 - 31 August 2011 1 March 11 - 31 August 11 |
| ER61 | 1 September 2011 - 29 February 2012 1 September 11 - 29 February 12 | |
| 2012 | ER12 | 1 March 2012 - 31 August 2012 1 March 12 - 31 August 12 |
| ER62 | 1 September 2012 - 28 February 2013 1 September 12 - 28 February 13 | |
| 2013 | ER13 | 1 March 2013 - 31 August 2013 1 March 13 - 31 August 13 |
| ER63 | 1 September 2013 - 28 February 2014 1 September 13 - 28 February 14 | |
| 2014 | ER14 | 1 March 2014 - 31 August 2014 1 March 14 - 31 August 14 |
| ER64 | 1 September 2014 - 28 February 2015 1 September 14 - 28 February 15 | |
| 2015 | ER15 | 1 March 2015 - 31 August 2015 1 March 15 - 31 August 15 |
| ER65 | 1 September 2015 - 29 February 2016 1 September 15 - 29 February 16 | |
| 2016 | ER16 | 1 March 2016 - 31 August 2016 1 March 16 - 31 August 16 |
| ER66 | 1 September 2016 - 28 February 2017 1 September 16 - 28 February 17 | |
| 2017 | ER17 | 1 March 2017 - 31 August 2017 1 March 17 - 31 August 17 |
| ER67 | 1 September 2017 - 28 February 2018 1 September 17 - 28 February 18 | |
| 2018 | ER18 | 1 March 2018 - 31 August 2018 1 March 18 - 31 August 18 |
| ER68 | 1 September 2018 - 28 February 2019 1 September 18 - 28 February 19 | |
| 2019 | ER19 | 1 March 2019 - 31 August 2019 1 March 19 - 31 August 19 |
| ER69 | 1 September 2019 - 29 February 2020 1 September 19 - 29 February 20 | |
| 2020 | ER20 | 1 March 2020 - 31 August 2020 1 March 20 - 31 August 20 |
| ER70 | 1 September 2020 - 28 February 2021 1 September 20 - 28 February 21 | |
| 2021 | ER21 | 1 March 2021 - 31 August 2021 1 March 21 - 31 August 21 |
| ER71 | 1 September 2021 - 28 February 2022 1 September 21 - 28 February 22 | |
| 2022 | ER22 | 1 March 2022 - 31 August 2022 1 March 22 - 31 August 22 |
| ER72 | 1 September 2022 - 28 February 2023 1 September 22 - 28 February 23 | |
| 2023 | ER23 | 1 March 2023 - 31 August 2023 1 March 23 - 31 August 23 |
| ER73 | 1 September 2023 - 29 February 2024 1 September 23 - 29 February 24 | |
| 2024 | ER24 | 1 March 2024 - 31 August 2024 1 March 24 - 31 August 24 |
| ER74 | 1 September 2024 - 28 February 2025 1 September 24 - 28 February 25 | |
| 2025 | ER25 | 1 March 2025 - 31 August 2025 1 March 25 - 31 August 25 |
| ER75 | 1 September 2025 - 28 February 2026 1 September 25 - 28 February 26 |
