Daisy Mackersie

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    MA (Oxon); GDL & BPTC (City)

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    “Very tenacious and bright.” – Legal 500, 2022

    “Hard working, dependable, approachable, technically very able.” – Legal 500, 2021

    “Extremely hard-working and diligent with top-notch drafting skills”Chambers UK 2020

    Daisy is an experienced junior practising in competition, procurement and regulatory law. She also has significant experience of wider public law matters, including information law and data protection.

    As a highly-regarded junior, Daisy acts with leading silks in complex and high-profile litigation. She also advises and appears in her own right, including for parties subject to regulatory investigations and, in procurement, for interested parties on matters of process and confidentiality.

    Daisy acts for commercial clients, government and public bodies. Clients have described her as a “rising star” of the profession, commending her drafting as “superb and extremely lucid”. She is an “excellent” advocate, dealing with oral submissions “effortlessly” and to “an extremely high standard”.

    She is currently instructed in two of The Lawyer’s Top 20 cases for 2020: the rail franchising litigation and the foreign exchange damages litigation.

    Recent significant cases include:

    • For Stagecoach in the rail franchising litigation (High Court and Court of Appeal)
    • For DAF in the trucks competition damages litigation
    • For J P Morgan in the foreign exchange damages litigation
    • For Whistl in Royal Mail’s appeal against Ofcom’s abuse of dominance decision in relation to postal services
    • For Care UK in the CMA’s action alleging breach of consumer protection law
    • News
    • Competition

      Daisy is an experienced competition law junior. She is currently instructed under leading silks in several significant competition damages actions and regularly advises commercial clients on competition law issues. She contributes to the leading practitioner text (Bellamy and Child: European Union Law of Competition).



      Her current and recent competition cases include:

      • Trucks —for DAF in individual damages claims
      • Royal Mail v Ofcom — for Whistl in Royal Mail’s appeal against Ofcom’s abuse of dominance decision in the postal sector: [2019] CAT 27
      • Foreign Exchange — for JP Morgan in individual damages claims and proposed class actions
      • Multilateral interchange fees – for various claimants bringing claims against Visa
      • CRT Glass — for Schott in a follow on damages claim
      • LCDs — for claimant public authorities bringing follow on damages claims
      • Pay for delay — for Merck in its appeal against the judgment of the General Court of the European Court of Justice


      Examples of Daisy’s competition advisory practice include advising (led and unled) on:

      • the lawfulness of proposed distribution arrangements
      • the legal obligations of companies, and other bodies, who hold a dominant market position
      • competition and state aid issues arising from new projects or initiatives from central Government and other public bodies
      • competition issues relating to trade organisations and industry bodies
      • complaints to the CMA and European Commission about the conduct of competitors
      • regulatory investigations concerning potential breaches of competition law
    • Public procurement

      Daisy has a well-established procurement law practice and is described in Chambers and Partners as having “excellent procurement law knowledge”. She acts for contractors and contracting authorities in complex and high-value litigation, as well as for interested parties with procedural concerns, such as the protection of confidential information.

      Daisy advises on contentious and non-contentious matters concerning all aspects of the procurement regime, including public contracts, utilities, concessions, and defence and security.


      Daisy’s recent significant procurement cases include:

      • Rail franchising litigation — for Stagecoach against the Department for Transport in the High Court and Court of Appeal: [2019] EWCA Civ 2259; [2020] EWHC 1569 (TCC)
      • HS2 (unled) — for an interested party in a challenge brought at the prequalification stage of the procurement for high speed railway rolling stock
      • MLS (Overseas) v Secretary of State for Defence — for MLS in relation to the procurement of worldwide port agency services by the Ministry of Defence: [2017] EWHC 3389 (TCC)
      • NATs v Gatwick Airport Ltd — for Gatwick Airport in relation to the procurement of air-traffic control services: [2014] EWHC 3728 (TCC)
      • Group M UK Ltd v Cabinet Office — for the Cabinet Office, defending an application to lift the automatic suspension: [2014] EWHC 3728 (TCC)
      • Mitie v Secretary of State for Justice — for Mitie, defending an application to lift the automatic suspension: [2020] EWHC 63 (TCC)
    • Commercial and consumer regulation

      Daisy acts for and advises regulators and businesses subject to regulatory investigation and enforcement, including under consumer protection legislation. Her experience spans a range of industry sectors, including telecommunications, utilities and financial services.


      Current and recent matters include:

      • Care UK — for Care UK in the CMA’s action alleging breaches of consumer protection legislation
      • advising the Payment Systems Regulator, a subsidiary of the Financial Conduct Authority, on new interchange fees regulation
      • advising Openreach on regulatory issues, including Ofcom market reviews
      • advising a party to a regulatory investigation by Ofgem
      • advising a party on potential regulatory action by the CAA in relation to consumer protection issues
    • Public, environmental and information law

      Daisy acts for claimants and public bodies in judicial review cases and statutory appeals and advises on public law issues including the application of the freedom of information and data protection legislation.


      Daisy’s recent public law work includes:

      • acting for the claimants against the CAA in relation to the classification of airspace: R (on the application of Lasham Gliding Society Ltd) v CAA [2019] EWHC 93 (Admin)
      • advising a leading environmental NGO on proposals for a third runway at Heathrow
      • advising WASPI in relation to the changes to the state pension age for women
      • acting for Friends of the Earth against the Secretary of State’s approval for the use of certain pesticides: R (on the application of Friends of the Earth) v Secretary of State for Energy and Climate Change [2015] EWHC 3283 (Admin)
      • acting for the Environment Agency in an appeal against its refusal to issue water abstraction licences for sites near to Special Areas of Conservation protected by the EU Habitats Directive
      • acting for the claimants in a judicial review of the Secretary of State’s decision to refuse to award a commercially valuable form of support for the production of renewable energy: R (on the application of Drax Power Ltd) v Secretary of State for Energy and Climate Change [2014] EWCA Civ 1153
    • Additional information

      Before joining Monckton in 2014, Daisy was a clerk in the House of Lords where, amongst other posts, she worked for the Conduct Committee on investigations into the abuse of expenses and on legislation in the Public Bill Office.

      She read philosophy and theology at Keble, Oxford and, on leaving the Lords, completed the GDL (Distinction) and BPTC (Outstanding) at City Law School. During her training, she won prizes and awards from Middle Temple, City University and the Bar Council.

    • What the directories say

      Public Procurement: “She is proactive and has fantastic judgement.” – Chambers UK, 2024

      Competition Law: “Daisy is seriously smart and strategic, super responsive and absolutely excellent with clients.” “She has great judgement and drafts really well.” “She has a really good client manner and an insightful legal mind, and is really good at delivering difficult messages to clients.” “Daisy is a pleasure to instruct.” “Her ability to understand and stress-test the most complex economic and econometric analysis is remarkable.” “Daisy is calm, confident, and has ferocious analytical skills.” – Chambers UK, 2024

      Leading Junior in Public Procurement: “Daisy is absolutely exceptional: fiercely bright, incredibly strategic, wonderfully practical and a joy to work with.” – Legal 500, 2024

      Public Procurement: “Very user-friendly, very clever and someone with great attention to detail.” – Chambers UK, 2023

      Competition Law: “Daisy is an excellent junior who is super smart, very clear in her advice, responsive and overall a pleasure to work with.” – Chambers UK and Chambers Global, 2023

      Leading Junior in Competition– Legal 500, 2023

      Rising Star in Public Procurement – Legal 500, 2023

      Public Procurement: “Reliable, all over the details and very knowledgeable about the issues in a case.” “She is very switched on and easy to deal with.” – Chambers UK, 2022

      Up and Coming in Competition Law: “She is excellent: clever, hard-working and user-friendly.” – Chambers UK and Chambers Global, 2022

      Public Procurement: “Very tenacious and bright.” – Legal 500, 2022

      Public Procurement: “Pays great attention to detail.” “She’s user-friendly and always thoroughly prepared.” – Chambers UK, 2021

      Competition: “Hard working, dependable, approachable, technically very able.” – Legal 500, 2021

      Public Procurement: “She was the brains of the operation.” – Legal 500, 2021

      Public Procurement: “Extremely hard-working and diligent with top-notch drafting skills and excellent procurement law knowledge.” – Chambers UK, 2020

    • Publications