Question to the Department for Science, Innovation & Technology:

To ask the Secretary of State for Science, Innovation and Technology, what data his Department holds on the numbers of (a) residential customers and (b) business customers that have moved from a PSTN telephone connection to a VOIP connection (i) when their contract expired (II) at the scheduled PSTN switch-off for their area (iii) for any reason in the last 12 months.

The Department does not hold this specific information on the Public Switched Telephone Network (PSTN) migration to Voice over Internet Protocol (VoIP).

Ofcom’s Connected Nations (2024) report (published 5 December 2024) states: “In the year to July 2024, 1.8 million residential customers who previously had a PSTN line migrated to a VoIP service. 53% (970,000 lines) of these were as a result of a provider-led migration, while the remaining 47% (870,000 lines) were as a result of customer-led migrations.”

The Department separately holds some information on the number of remaining PSTN lines and the number of migrations per quarter for the larger communications providers. As of December 2024, there were circa 6.5 million active PSTN lines remaining.