Glossary
MNO, MVNO, eSIM, PAC code, Go Roam, 5G Standalone, umlaut — every piece of UK mobile jargon explained simply and clearly.
A company that owns and operates its own physical mobile network — masts, radio equipment, licensed spectrum, and core network. The three UK MNOs in 2026: EE (BT Group), O2 (Virgin Media O2), and VodafoneThree (Vodafone + Three).
A company providing mobile services without owning physical network infrastructure. MVNOs buy wholesale access from MNOs. Examples: Tesco Mobile and Giffgaff (on O2); SMARTY and iD Mobile (on Three); Lycamobile (on EE). Usually cheaper than MNO direct prices.
Fourth Generation mobile. Launched in the UK by EE on 30 October 2012 — 18 months before competitors. Typical real-world speeds 20–100 Mbps. LTE (Long Term Evolution) is the underlying technical standard. Covers 99%+ of UK population on all three MNOs.
Fifth Generation mobile. Launched in the UK by EE on 30 May 2019. Speeds 100 Mbps–730+ Mbps. Lower latency and greater network capacity. Available in 500+ UK towns and cities. Included free on almost all current UK mobile plans.
Pure end-to-end 5G network using an entirely 5G-native core rather than relying on 4G infrastructure. Enables true ultra-low latency (under 10ms), network slicing, Voice over 5G, and better battery efficiency. EE (5G+) covers 50M+ people; O2 (5G+) covers 85%+ UK population in 2026.
Porting Authorisation Code — a free 9-character code authorising mobile number transfer between UK networks. Text PAC to 65075; receive in 60 seconds. Valid 30 days. Transfer completes within one working day. Cannot be refused, delayed, or charged for by your current network.
Service Termination Authorisation Code — requested by texting STAC to 75075. Allows you to leave your current network without transferring your number. Used when you want a fresh start with a new number. Also includes your termination fee information.
Embedded SIM — a digital SIM permanently built into the device hardware. Activated online via QR code or app in minutes. Compatible with iPhone XS/XR and later, Samsung Galaxy S20 and later, Google Pixel 3 and later. Supports dual SIM on most modern devices. All major UK networks support eSIM.
Three UK's international roaming programme. Three tiers: Go Roam in Europe (49 EU destinations, on Value/Complete plans), Go Roam Around the World (22 major global destinations), Go Roam Around the World Extra (163 destinations total on Complete plans). 12GB data fair use monthly cap applies when roaming.
O2's free loyalty rewards app for all O2 mobile and Virgin Media broadband customers. Delivered 8M+ rewards in 2025 including weekly free Greggs treats, discounted Vue cinema tickets (4 for £18/month), £150 off lastminute.com, and 48-hour concert presale access.
Europe's first direct-to-device satellite mobile service, launched 26 February 2026 using SpaceX Starlink Direct to Cell. Works on Band 3 (1800 MHz). Extends O2's UK landmass coverage from 89% to 95%. Compatible with Samsung Galaxy S25 series at launch. £3/month bolt-on.
A contractually permitted yearly increase to your monthly mobile bill. Since 17 January 2025, Ofcom requires the exact £/p amount to be stated at point of sale. EE: +£2.50/month SIM-only. O2: +£2.50/month. Legacy contracts on old CPI+3.9% formula faced a 7.3% rise in April 2026.
Company formed from the Vodafone UK + Three UK merger on 31 May 2025. UK's largest mobile network — 28.8M customers. £11B 10-year investment. Both brands continue operating. Vodafone Group announced a £4.3B buyout of CK Hutchison's 49% stake in May 2026.
Vodafone's premium international roaming tier covering 83 countries across Zones A (4 destinations, free), B (47 European destinations), and C (32 worldwide destinations including USA, Canada, Australia). Included on Unlimited Max Xtra Global Roam plans with a 25GB monthly fair-use data cap when roaming.
Routes phone calls over your broadband WiFi when mobile signal is poor. Supported by all major UK networks and most devices. Enable in phone Settings → Calls or Phone. No extra network charge. Dramatically improves call quality in thick-walled buildings and underground environments.
Sharing your phone's mobile data connection with other devices (laptops, tablets) via a personal WiFi hotspot. Included on most UK plans. Some unlimited plans impose a tethering fair-use cap — check your specific plan's terms.
The UK's independent communications regulator. Governs spectrum licensing, sets consumer protection rules (including the January 2025 pounds-and-pence price rise transparency rule), manages number porting, and publishes annual coverage and quality reports.
An independent annual mobile network quality test conducted by German testing firm umlaut (also known as connect). Uses drive tests, walk tests, and crowdsourced data to score networks out of 1,000. EE has won the UK test every year since 2014 — 11 consecutive years, scoring 920/1000 in 2026.