Public interest intervention notices: when ministers change merger law mid-deal
In short: the Secretary of State may give a public interest intervention notice (a notice bringing grounds other than competition into a merger decision) on a public interest ground that is not yet in section 58 of the Enterprise Act 2002, and must then act to add that ground by order while the deal is under review. The Secretary of State by order, and Parliament by statute, changed the grounds for deals under review in 2008, 2024 and 2026, and the risk is greatest in regulated sectors and sectors of national importance.
A buyer that signs a large UK acquisition assesses its merger control risk against the law in force on the day it signs, including the list of public interest grounds on which a minister may intervene. The Secretary of State may intervene on a ‘public interest’ ground that the list does not yet contain, and add it by order while the deal is under review. The decision on the deal may then depend on a ground that did not exist at signing. The most recent ground, the continuity of telecommunications supply, came into force on 13 October 2026, eight days after the notice that relied on it.
How the Secretary of State adds a public interest ground after a deal is announced
The Secretary of State may give a public interest intervention notice where a public interest consideration may be relevant to a merger within UK merger control, under section 42(2) of the Enterprise Act 2002. That consideration is one specified in section 58, or one that is “not so specified but, in the opinion of the Secretary of State, ought to be so specified” (section 42(3)). Having relied on an unspecified ground, the Secretary of State must act as soon as practicable to have it finalised (section 42(7)), by an order under section 58(3). An order may also apply to cases already under consideration (section 58(4)(b)).
An order adding a ground may come into force before Parliament votes on it, and both Houses of Parliament must approve it within 28 days or it ceases to have effect; no account is taken of any time when Parliament is dissolved, prorogued (between sessions) or adjourned for more than four days (section 124(7) and (8)). While a ground awaits approval, the Secretary of State may not rely on it to justify a merger that the Competition and Markets Authority (CMA) has found may substantially lessen competition. In that case the Secretary of State may delay the decision until the ground is approved, for up to 24 weeks from the notice, if there is a realistic prospect of approval in that time (section 46(4) and (5)). A ground still awaiting approval at 24 weeks must be disregarded (section 46(3)).
Three changes of law made while a deal was under review
The financial stability ground was added for the Lloyds TSB acquisition of HBOS during the 2008 financial crisis. The Secretary of State gave an intervention notice on 18 September 2008, the day the merger was announced, relying on financial stability as a ground that ought to be specified. The order inserting section 58(2D) came into force on 24 October 2008 and applied to cases already under consideration (SI 2008/2645, article 1(2)). The Office of Fair Trading found a realistic prospect of a substantial lessening of competition in three markets, including personal current accounts and mortgages. The Secretary of State accepted that finding, as section 46(2) required, and decided not to refer the merger for a second-stage (phase 2) investigation because its benefit to financial stability outweighed the competition concerns. The Competition Appeal Tribunal dismissed a challenge to that decision in Merger Action Group v Secretary of State for Business, Enterprise and Regulatory Reform [2008] CAT 36.
The foreign state newspaper regime came by statute. RedBird IMI’s proposed acquisition of Telegraph Media Group led to intervention notices on the existing media grounds in November 2023 and January 2024. In March 2024 the Government added a regime for mergers involving newspapers and foreign powers to the Digital Markets, Competition and Consumers Bill, after an attempt by a UAE-backed firm to take over Telegraph Media Group (House of Commons Library). The regime, now Chapter 3A of Part 3 of the Enterprise Act 2002, applies to arrangements in progress on or after 13 March 2024, ten weeks before Royal Assent on 24 May 2024 (section 130(2) and (3) of the 2024 Act). The Secretary of State must give the CMA a notice where there are reasonable grounds to suspect that a foreign power may gain control of, or influence over, the policy of a newspaper (section 70A). On 16 October 2026 the Secretary of State decided not to refer the RedBird IMI bids (CMA case page), or a later bid for the title by Daily Mail and General Trust (CMA case page), because neither was still in progress or in contemplation.
Section 58(2EA) now contains a telecoms-specific ground: the need to maintain the continuity of the supply of telecommunications services to prevent disruption to the economy and society of the United Kingdom, in particular to public services, critical national infrastructure and customers who are or may be vulnerable. The Secretary of State gave the notice that relied on it on 5 October 2026, made the order and laid it before Parliament on 12 October, and the order came into force on 13 October 2026 (SI 2026/1075). Unlike the 2008 order, the 2026 order does not apply the ground to pending cases; the ground counts in the pending decision because the Secretary of State relied on it in the notice before it was specified. Both Houses must approve the order within 28 days of its being made. There was no formal consultation because of the urgency, and the ground is “intended for use only in exceptional circumstances involving continuity risks” (Explanatory Memorandum, paragraphs 7.1 and 9.3).
The table below lists the changes to the public interest grounds.
| Year | Change to the grounds | How the law changed | Used for a deal already under review |
|---|---|---|---|
| 2008 | Stability of the UK financial system added (section 58(2D)) | Order under section 58(3), in force 24 October 2008 | Yes; article 1(2) applied it to pending cases |
| 2020 | Capability to combat public health emergencies added (section 58(2E)) | Order under section 58(3) | No deal named in the order |
| 2024 | Foreign state control or influence over newspapers (Part 3, Chapter 3A) | Primary legislation, Royal Assent 24 May 2024 | Yes; applies to arrangements in progress on or after 13 March 2024 |
| 2025 | Newspaper grounds extended to all news media, including broadcast news (section 58(2A) and (2B)) | Order under section 58(3), in force 24 July 2025 | No deal named in the order |
| 2026 | Continuity of telecommunications supply added (section 58(2EA)) | Order under section 58(3), in force 13 October 2026 | Yes; the notice of 5 October 2026 relied on it before the order was made |
Which deals carry the risk
Any deal within UK merger control carries the risk until the CMA makes its first-stage (phase 1) decision. The Secretary of State may give a public interest intervention notice only where there are reasonable grounds to suspect a relevant merger situation, as defined in section 23 of the Enterprise Act 2002. Since 1 January 2025 that means the target has UK turnover above £100 million; or the merger creates or increases a share of 25% or more of the supply of goods or services of a particular description in the UK, and a party has UK turnover above £10 million; or one party has a share of supply of 33% or more and UK turnover above £350 million, and the other has a link to the UK. For newspaper and broadcasting mergers the Secretary of State has powers below those thresholds (section 59). No notice may be given once the CMA has referred the merger, decided not to refer it or accepted undertakings in place of a reference (section 42(1)), so the Secretary of State may give the notice at any time until the phase 1 decision. Within that window the CMA assesses competition in the usual way, as in the nexfibre/Substantial inquiry, and the Secretary of State weighs that assessment against the grounds in the notice.
The grounds added since 2008 concern banking stability, public health, news media and telecoms supply, each a closely regulated sector or one of national importance, and that is where the risk of a further ground is greatest. A new ground may support a deal as well as count against it. An anti-competitive outcome is adverse to the public interest unless a relevant public interest consideration justifies it (section 45(6)), and the Secretary of State cleared a merger on the financial stability ground that the Office of Fair Trading had found may substantially lessen competition.
Implications for deal timetables and documents
Once the Secretary of State gives a public interest intervention notice, the decision whether to refer the merger is the Secretary of State’s. The CMA reports by the date set in the notice. Where the CMA has found that the merger may substantially lessen competition and a ground still awaiting approval is mentioned in the notice, the Secretary of State may then wait up to 24 weeks from the notice for Parliament to approve it, if there is a realistic prospect of approval in that time. For a completed merger, a reference must be made within four months of the later of completion and the facts being made public, subject to extension (section 24, applied by section 42(5) and (6)). The notice can come on the day a deal is announced, as it did in 2008.
Parties setting a long-stop date (the date after which a party may end the deal if the conditions are not met) by reference to the CMA’s statutory timetable should consider whether to allow for a delay of up to 24 weeks while Parliament considers a new ground, which arises only where the CMA has found a substantial lessening of competition. A condition or termination right drafted by reference to the grounds in section 58 at signing may not cover a notice on a ground added later, whereas one drafted by reference to any intervention notice under section 42 would. Certain-funds periods (during which lenders may not withdraw acquisition finance), and the triggers for any break fee, are measured against the same timetable. The Epiris offer for Gamma Communications shows how clearance conditions are set out in a UK telecoms deal, and the deal structuring and negotiation page covers conditions in regulated transactions.
Perspective
I read the 2026 order as confirmation that the list of section 58 grounds is open. Under the National Security and Investment Act 2021 the test is national security in every case, and the 17 sectors in which acquisitions must be notified are listed in regulations (SI 2021/1264, regulation 2), so a buyer knows in advance whether its deal must be notified and which test the Secretary of State will apply (the regime in practice). Under section 58 the Secretary of State may change what is assessed after a deal is announced, and in 2008 and 2026 did so within weeks.
For the parties to a large UK deal in a regulated sector, the time limits are 28 days for Parliament to approve an order, the 24-week limit in section 46 and, for a completed merger, the four months in section 24.
Frequently asked questions
Can the Secretary of State intervene in a merger on a public interest ground that is not in section 58?
Yes. The Secretary of State may give a public interest intervention notice on a ground that, in the Secretary of State’s opinion, ought to be specified in section 58 of the Enterprise Act 2002 (section 42(3)). The Secretary of State must then act as soon as practicable to have it specified by order, and both Houses of Parliament must approve the order within 28 days or it ceases to have effect (section 124(7)).
Can a new public interest ground apply to a deal already under review?
Yes. An order may apply to cases under consideration before it was made (section 58(4)(b)), and the 2008 order applied to them in terms (article 1(2)). Separately, a ground relied on in a notice before it is specified counts in the decision once Parliament approves it, as with the 2026 telecoms ground. Primary legislation can have the same effect: the foreign state newspaper regime applies to arrangements in progress on or after 13 March 2024.
How long can a public interest decision on a merger take?
Where the CMA has found a substantial lessening of competition and a new ground awaits Parliament’s approval, the Secretary of State may delay the decision for up to 24 weeks from the notice, if there is a realistic prospect of approval in that time. For a completed merger, the four-month limit in section 24 applies, subject to extension. The CMA reports by the date set in the intervention notice. A reference starts a second-stage (phase 2) investigation by the CMA.
For advice on public interest and merger control risk in a regulated transaction, contact Rob Bratby at Bratby Law.
