The ‘not spot’ mobile postcodes of the South East
CLA reveals the worst affected and calls for urgent action
You may expect the South East of England to be one of the best regions in the world for mobile network quality – but some postcodes have become such ‘not spots’ that the majority of users are suffering issues.
The Country Land and Business Association (CLA) has compiled a ‘list of shame’, highlighting the areas that are struggling with substandard network quality.
The CLA, a membership organisation that represents farmers and rural businesses, has used the latest data from Which?, comparing the percentage of time users have a good experience across providers.
We can reveal users have a good experience:
- Just 41% of the time on Three in the OX15 postcode area
- 43% of the time on Three in CT14
- 47% on Three in SO24
- 47% on Three in TN21
- 48% on O2 in SP6
- 48% on Three in TN33
- 49% on O2 in RH17
- 49% on Three in SO22
- 50% on Three and 53% on O2 in BN8
- 51% on O2 in TN9
- 52% on Three in CT14.
'How can businesses operate?'
CLA Director Tim Bamford said: “Reliable mobile coverage is vital for rural economic growth – how can businesses operate with such poor network quality?
“The government recently announced the upgrading of 100 mobile masts, but none were in the South East and our region urgently needs attention. You can be a few miles from London but have no bars of signal on your phone.
“Many parts of the countryside remain in the digital wilderness, impacting businesses and communities, and more work needs to be done to close the urban-rural connectivity divide.
“Landowners are willing to host masts on their property but must be fairly compensated, and the CLA will speak to any operator so all of rural Britain can benefit from the digital revolution.”
The figures compare poorly to many remote parts of the north of England. For example, users have a good experience 71% of the time on O2 in the CA8 postcode in Cumbria, while the figure rises to 77% on Three in TD9 in the Scottish borders.
The data
The data is collected from over one million mobile handsets in the UK running apps by Opensignal, an independent network analytics company. Opensignal specializes in measuring real-world mobile network experience, and their data is used by regulators, media, and the telecom industry worldwide.
The percentage scores represent “how often is the network good enough” to support everyday tasks like browsing the internet, streaming videos, or making video calls, all without major slowdowns or disruptions.
To calculate these scores, several aspects of network performance are considered, including download throughput (min. 5Mbps), upload throughput (min. 1.5Mbps), and latency (max. 50ms). The thresholds used are based on the performance requirements of common mobile applications, particularly those that place higher demands on the network. The percentage score reflects how often test results meet these standards on 4G and 5G networks.
The scores are based on data collected over a 12-month period, from November 1, 2024 to October 31, 2025.