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Number Porting

In order to port a Geographic Number from BT or Cable & Wireless, the Geographic Number Portability form (GNP Letter of Authority ) needs to be completed by the subscriber of the number.


The GNP Letter of Authority is provided in Word format, please try and complete in Word and not manually.

If the line(s) that are to be ported are currently held by BT directly i.e. you receive a bill from BT then you should enter the BT account number on the GNP Letter of Authority.

You will also need to provide a photocopy/scan of the cover page of the BT bill clearly showing the account number (top left hand side first 10 digits) and address. Or if the line(s) that are to be ported are currently held by a BT Wholesaler and you receive a bill from an independent telecoms company (e.g. TalkTalk), then you should leave the account number box empty and you do not need to provide a copy of any bill.

In the Site address box please enter the address that the number(s) are currently live at. Please include the Post Code. This is normally the same as the BT bill and should be completed accurately.

In the Telephone Number(s) to be ported: box, please ensure you include all associated numbers and or Direct Dial-In (DDI) numbers.

Once this has been completed it must be printed on your letter head.

The GNP Letter of Authority must be signed by an authorised user in ink.

Associated Numbers

If the BT bill contains any associated numbers which are not to be ported (i.e. additional numbers on a BT Highway) we must be made aware in writing whether or not you would like to cease the numbers. (On BT Highway Accounts you may not be aware of associated numbers).

Lead/Guide Times

Below are details and approximate guide times for processing different types of geographic numbers to be ported from BT. If there is any problem our Porting team will contact you. If the number is part of a range/area that we do not currently have a Porting agreement for, it will need to be arranged and will increase the time of the portability process.

Single analogue line request 10 working days
Up to 10 lines single analogue lines 21 working days
Multi Line - 10 lines or less 14 working days
Multi Line - 11 or greater (or a Centrex site) 24 working days
Simple DDI 24 working days
Complex DDI 30 working days
ISDN 10 lines or less 14 working days
ISDN 11 lines or less 30 working days
User not contracted to BT

If the end user is not contracted to BT directly then as the Gaining Party a request must be sent to the Losing party with notification of the customer’s authority to port and a request for the range holder account details to include the BT wholesale CSS account number.

It is your responsibility to obtain the CSS number from the existing provider.

BT RedCare

We cannot port number(s) with BT RedCare attached to them. RedCare needs to be removed first before we can proceed with the port request. There may be a charge from BT and their Security supplier for transferring a RedCare line.

Cease of Lines

The lines will cease automatically and unless prior notification is submitted. Once the port takes place any diverts that have been placed on the line will automatically cease once the line has ceased. You should then contact BT for a final bill.

Broadband on the Line

Please be aware that if there is broadband on the line to be ported, once a change happens to the line, the broadband will automatically fall off.

Notifications of Port

Port dates will be given out. Please let us know as soon as possible if the port date is not convenient so we can request that it is rescheduled.

Provisioning of Numbers/Equipment

Please be advised that all numbers/equipment need to be provisioned 24 hours before the porting process.

Pre-Port test calls

Pre-port test calls will commence at 9am on day of port to confirm correct termination. If pre-port tests are confirmed, then the port will go ahead during a window slot of 10.00am until 1.00pm. Post-port test calls will be made to confirm traffic routing over the network and an email or phone call will be made to confirm that the port was successful. If the port was unsuccessful, another date will be rescheduled.

Directory Enquiries Geographic Number Registration

WemTel can register a customer's geographic number with BT Directory enquiries. The number is registered using the BT DQ Manual Process. The customer needs to complete a Directory Enquiries Information Template for each number they want registered and send them by post or email to the address below. The WemTel provisioning team will then review and lodge the registration with BT DQ.

'Things to remember'
  • If you are porting a DDI range you can only port the entire range and not part of the range.
  • If the line you wish to port has associated numbers you must advise us what you wish to do with those numbers either; Port all / disconnect / leave live.
  • You must advise us if the number has remote call forwarding activated. If this is the case please provide the postcode of the BT exchange that the line is forwarding from. This information is easily obtainable by requesting from BT (try calling 0800 800 150).
'Things to avoid'
  • Currently Fax lines are not fully supported on the VoIP platform so please ensure you have an analogue line in place for fax.
  • Don't guess, if you're not sure of something its worth double checking as if we submit a port request to BT incorrectly (like the complete DDI range or the Post Code), the port will be rejected causing delays and a rejection charge being passed on to you.
Submission and Summary

When this GNP Letter of Authority has been completed and printed on company letterhead it needs to be sent to WemTel together with the items listed below to the following address:

Savoy House
Savoy Circus
W3 7DA

or scanned in PDF, JPEG or WORD format ONLY and emailed with the subject line: 'Port Request – Company Name' to together with:

  1. A copy of the latest BT Bill for the number
  2. Confirmation of the line type: Single Analogue / MultiLine / ISDN2e / ISDN 30
  3. Any associated numbers: Provide all the CLI's and instructions to Port All / Disconnect / Leave Live
  4. For a DDI range or a multi-line with more than 11 lines, we also need the Capacity Planning Questionnaire Form completed
  5. A Directory Enquiries Information Template if you require directory listing. Once received and submitted, you will receive an acknowledgement and we will contact you with a date for porting. If the port is rejected for any reason we will contact you for any further information that may be required.

Once received and submitted, you will receive an acknowledgement and we will contact you with a date for porting.

Resubmission Fees

If the port is rejected for any reason we will contact you for any further information that may be required. Should a number port be rejected by the carrier for incorrect information, a resubmission fee of £25 will apply. Correct information will need to be submitted within 24 hours after which time the request will time out and require a new submission including associated charges. Requests for information not responded to within 10 days will result in cancellation of the port.


"It was essential to us as a business to maintain our existing number when we moved offices and the WemTel service provided this and more through their amazing SIP Gateway service. It now means I don't have to rely on ISDN for my phones which provides us with substantial cost savings."

Martin Banford, Placement UK

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