Matrix is continuing its raid on magic circle sets as it shifts its focus from public law to the commercial arena.
Former solicitor general of Australia Gavan Griffiths, door tenant at Essex Court, specialises in commercial law and will become an associate tenant at the 33-strong set.
His practice includes sitting as an arbitrator at the International Centre for Settlement of Investment Disputes (ICSID), which is situated at the World Bank.
Matrix chief executive Nick Martin says all associate members have established practices outside the remit of the UK Bar Council. He says: "[Griffiths] will not just act as a figure of grandeur. He's a highly-regarded arbitrator and lawyer who will help to build our growing practice."
Essex Court chief clerk David Grieff says: "Griffiths is a non-practising UK lawyer, but we're sorry to lose an association that has existed for more than 20 years."
Griffiths' appointment coincides with 39 Essex Street's Lord Dan Brennan QC's decision to join Matrix, a specialist in personal injury (PI) and clinical negligence.
Although Matrix was launched as a public and human rights set in January, it has begun to hire barristers with a commercial background.
Senior junior Anthony White, who has a commercial and employment practice, joined Matrix from Cloisters this year.
However, Brennan, the former chairman of the Bar Council, has expressed an interest in developing environmental law.
Martin says: "Dan is known as a leading PI advocate but also has an impressive international and environmental practice."
In August, Matrix bolstered its environmental law practice by taking on Kate Cook, formerly a legal adviser at the Department of the Environment, Transport and the Regions.