Will there be a more streamlined UK merger control process?

The Competition and Markets Authority (CMA) published updated guidance on 19 December 2025, forming part of its wider drive to improve its "4Ps" (pace, predictability, proportionality and process). Will it deliver?

Early engagement pays dividends

Parties can now engage with the CMA on remedies at any point prior to the substantial lessening of competition (SLC) decision, including up to the Phase II interim report.

The earlier the engagement, the more time the CMA has to consider evidence and request further information. The message is clear: come prepared with sufficient evidence and engage in full and frank discussions.

Pre-notification: more structure, more control

Parties can now have informal update calls with the CMA on case progress, including areas of CMA focus and third-party feedback, and can request more than the usual 40 working days.

In more difficult or complex cases, the parties may choose to involve the Phase I decision-maker at this stage. Alternatively, the decision-maker could deem their involvement appropriate based on remedy risks or simultaneous reviews by other competition authorities, though the parties' consent is still required.

Phase I: dedicated remedies discussions

After receiving an issues letter, the CMA will offer a separate meeting to discuss undertakings-in-lieu (UILs), usually within two working days of the parties' response deadline. The effectiveness of these meetings can be improved by providing the proposed UILs in advance.

While the updated merger remedies guidance removes the presumption against behavioural remedies at Phase I, parties must still demonstrate sufficient evidence of their effectiveness and proportionality.

Fast track UILs

Parties can request a fast track for UILs for certain markets under investigation, though remedies still need to be "clear-cut",  with no material doubt as to effectiveness and feasibility to implement.

Parties considering "fix-it-first" divestitures that will take place alongside the main transaction should use the fast track process, particularly where the CMA has doubts about their effectiveness or certainty. It will consider the risks of the divestiture, including the composition and purchaser of the business to be divested.

Phase II: early remedies meetings

Where sufficiently advanced proposals are submitted within four weeks of the initial substantive meeting, an early remedies-focused meeting with the Inquiry Group may be offered before the interim report. Proposals should be as detailed as possible to receive detailed feedback from the Inquiry Group.

The revised guidance points out that appeals to the Competition Appeal Tribunal (CAT) do not suspend timelines or the effect of decisions unless the CAT directs otherwise, so the CMA may accept final undertakings while an appeal is pending.

Completed mergers: no special treatment

The CMA adopts the same process for both anticipated and completed mergers, meaning it will not normally take into account the costs of divestment when considering remedies for completed mergers. Worse still for a purchaser, the CMA may even require it to divest more than it originally purchased where the competitive potential of the business has reduced over time.

Multi-jurisdictional reach

The CMA confirms it may impose remedies covering conduct outside the UK where the relevant party is incorporated or does business outside the UK. The CMA may also accept remedies conditional on foreign approvals expected within a reasonable timeframe.

Osborne Clarke comment

The CMA process has come under criticism for being unduly lengthy, particularly the pre-notification stage (which often lasts three to four months, and sometimes considerably longer) and the Phase I process. The new guidance seeks to address this criticism.

But will it work? There is a risk that a "pre-pre-notification" period may develop, with parties and the CMA seeking to maximise early engagement. Further, under newly-proposed reforms, merger parties and the CMA would be able to agree post-Phase I extensions for remedies to avoid lengthy Phase II processes, essentially adding a new step if a Phase II referral is made anyway.

While streamlining is to be welcomed, whether these reforms will deliver remains to be seen.