Mr Lachlan W L Armstrong QC

Contact Details




Lachlan practices in general commercial, securities, competition and insurance litigation in the Federal Court and all State superior courts.

He has particular experience in complex litigation.  He has advised or appeared in more than 60 class actions since 1998, in most Australian jurisdictions and covering a very wide range of practice areas.  The most prominent of the class actions in which he has been centrally involved include:

  • as shareholder actions - GIOAristocratCentroSigma and GPT (for claimants) and Harris Scarfe and Nufarm (for defendants)
  • other investor litigation - Opes Prime (2007) and Lehman Brothers (2012)
  • cartel actions - VitaminsAmcor/Visy and Air Cargo cartel class actions
  • mass tort proceedings - the five Victorian "2009 Black Saturday Bushfire class actions" including the "Matthews v. SPI – Kilmore Bushfire" class action (VSC, 2010-2014), the 2014 Parkerville Bushfire (WASC) multi-plaintiff action, and the Victorian "Abalone Virus" class action.

Outside class actions, Lachlan has extensive experience in:

  • liquidation-related proceedings, including the “APCH” liquidator recovery actions in the Supreme Court of Victoria
  • insurance litigation, including representing the successful ‘Johnston’ group in their challenge to insurers’ assertions of subrogation rights in Johnston v. Endeavour Energy [2015] NSWSC 1117 and
  • competition law, most recently acting for the ACCC in ACCC v. Medibank Private Ltd (FCA 2016).  Lachlan has also acted in successful applications to ACCC for authorisations under Part VII of the Competition and Consumer Act, such as the North East Winegrowers application (2008). 

Lachlan advises in a wide range of commercial, insurance and general litigation matters.  He appears in the Supreme Courts of all States, and in the Federal Court. 

Other matters

Lachlan was the originating author of the class actions commentary in the Butterworths Federal Court Practice looseleaf, and is a member of the Law Council of Australia committee on class action litigation.

Liability limited by a scheme approved under Professional Standards legislation.

Formal Details 0

  • Admitted to Practice
    01 April 1996
  • First Signing Bar Roll
    23 November 2000
  • Date Appointed Silk
    26 November 2014
  • Qualifications
    B.Comm (Melb), LLB (Hons) (Melb)

Areas of Speciality

  • Banking & Finance
  • Corporations & Securities
  • Equity
  • Insolvency Law
  • Insurance & Professional Negligence