Ofcom investigates BT and Three UK over recent widespread outages

The UK telecoms regulator Ofcom has launched formal probes into BT Group and Three UK following significant outages this summer, raising questions about operator resilience and compliance with regulatory obligations.

The UK telecoms regulator Ofcom has opened formal investigations into BT Group and Three UK after separate summer outages that left thousands of customers unable to make or receive calls, including to emergency services. The enquiries, announced on December 15, 2025, follow high‑profile incidents on both operators that prompted widespread disruption across the country. ^[1][2][3]

BT experienced a software‑related interconnect outage on July 24–25, 2025, which affected calls to and from the EE network and other operators, while Three notified Ofcom of a distinct voice service failure on June 25, 2025 that similarly impaired users’ ability to contact other networks and emergency services. Industry and regulator accounts say the outages were UK‑wide and prevented some customers from completing vital calls. ^{[1][2][3][4][5]}

Ofcom said it will assess whether either company failed to meet legal and regulatory obligations to take appropriate measures to prevent network failures and to mitigate their impact when they occur. The regulator’s statements make explicit reference to obligations under the Communications Act 2003 and the Electronic Communications (Security Measures) Regulations 2022 as part of the scope of the enquiries. Ofcom will examine root causes, resilience arrangements and whether operators satisfied the notification and remedial requirements set out in the rules. ^[3][4][5]

A BT spokesperson said in an emailed statement: “We will co-operate fully with Ofcom throughout the investigation and apologise again for any issues caused by this incident.” The company has acknowledged the July software fault and said it is engaging with the regulator as Ofcom carries out its review. ^[1]

Three UK did not immediately respond to a Reuters request for comment, according to reporting. Background material notes Three UK as the smallest of the four major mobile operators and describes its recent corporate evolution and market position; it has been recognised in consumer surveys for data performance and offers 4G and 5G services to a substantial customer base. Ofcom’s separate public notices about the June incident set out the areas of regulatory concern the regulator intends to probe. ^[1][2][3][4]

The investigations occur against a backdrop of recurrent network faults at UK mobile operators: past outages involving Three have prompted thousands of customer reports and public apologies from the operator in earlier episodes. Industry observers say repeated high‑impact incidents increase scrutiny of operator resilience and could lead to enforcement action or remediation requirements if Ofcom finds breaches of regulatory duties. ^[6][7]

##Reference Map:

• ^[1] (ARY News) – Paragraph 1, Paragraph 2, Paragraph 4, Paragraph 5
• ^[2] (Reuters) – Paragraph 1, Paragraph 2, Paragraph 5
• ^[3] (Ofcom announcement) – Paragraph 1, Paragraph 2, Paragraph 3, Paragraph 5
• ^[4] (Ofcom , Three investigation page) – Paragraph 2, Paragraph 3, Paragraph 5
• ^[5] (Ofcom , BT investigation page) – Paragraph 2, Paragraph 3
• ^[6] (The Guardian, Feb 12 2024) – Paragraph 6
• ^[7] (The Guardian, Jan 23 2025) – Paragraph 6

Source: Fuse Wire Services