From September 12, 2023, new regulations came into effect, governing the requirements for sender IDs used to send messages to the UK. Messages sent from sender IDs that don't meet these requirements are likely to be blocked, so it's important you take the necessary steps if you wish to send messages to the UK.
UK Sender ID requirements
- All international numeric Sender IDs will be blocked (non-UK numeric sender IDs).
- Short codes that don’t follow UK short code format (five digits starting with 6-8) will be blocked.
- Sender IDs should be brand centric; alphanumeric sender IDs (formerly alpha tags) containing generic senders will be blocked.
- This means that all alphanumeric sender IDs must be recognizably associated with your brand. For example, a company called "ACME Co." should ideally use "ACME" or similar as their alphanumeric sender ID. If the message is for an ACME customer to verify their identity, then sending from the alphanumeric sender ID "VERIFY" will be blocked, because the word "Verify" is not recognizably associated with ACME.
- Alphanumeric sender IDs may only contain the characters: a-z, A-Z, 0-9, and - or _
Second blocking phase: 31st October 2023:
From 31 October 2023, BT has blocked sender IDs and all their character sub-variations on the standard connections. It is also planned, from 31 October 2023, to restrict use of alphanumeric sender IDs/Alphanumeric sender IDs containing additional generic terms (and their character variations). A list of alphanumeric sender IDs that were blocked from 31 October 2023 can be found here.
- The error code that will be returned to customers for traffic blocked due to non-compliant sender IDs will be:
15 SCREENING ERROR "Screening block" (permanent error) - Flash messaging not supported in the UK
UK | Blocked alphanumeric sender IDs
The use of alphanumeric sender IDs containing additional generic terms (and their character variations) when sending SMS messages to the UK is restricted.
The below table contains a list of the alphanumeric sender IDs that are likely to be blocked.
| 1TimePin | Bank | Discount | NoReply | Repayment | SMSVerfiy |
| 2FA | Banking | Energy | Notify | Reply | Support |
| Accept | Bill | Fraud | OneTimePin | Respond | System |
| Access | Billing | Help | Order | Save | Text |
| Account | Call | Info | OTP | Saving | Trace |
| Active | Card | InfoSMS | OTPSMS | Scam | Track |
| Admin | Caution | ISA | Package | Savings | Tracking |
| Advise | Certify | Key | Parcel | Schedule | Trust |
| Alert | Check | Loan | Pay | Secure | TXT |
| Allow | CloudOTP | Login | Payment | Security | Update |
| Allowance | Code | Logistics | Pin | Service | Updates |
| App | Collect | LogMeIn | PinCode | Shipping | Validate |
| Appointment | Collection | Logon | Post | Sign | Verify |
| Approve | Confirm | Malware | Protocol | Signin | VerifySMS |
| Approved | Contact | Message | Purchase | Signon | VerifyMe |
| Auth | Control | Mobile | Ratify | SMS | Virus |
| AuthMsg | Courier | Mortgage | Rebate | SMSAuth | Warn |
| Authorise | Delay | MSG | Receipt | SMSCode | Warning |
| AuthSMS | Deliver | MsgAuth | Refund | SMSInfo | Winner |
| Aware | Delivery | Network | Reminder | SMSOTP |
Consequences of Non-Compliance
UK carriers take smishing (phishing via SMS) very seriously. Customers sending SMS messages after September 12, 2023 from sender IDs that don't conform to the above requirements may incur liquidated damage charges of up to £5,000.