Allen & Overy (A&O) German dispute resolution head Daniel Busse has left to launch his own boutique, while the firm has boosted its London practice with a partner hire from public international law specialist Volterra Fietta.

The new German boutique will be called Busse Disputes and will officially launch in March next year. Until then, Busse will remain practising in A&O's Frankfurt office.

He will exit the magic circle firm after eight years as German litigation head. He joined A&O in that role from legacy Lovells, where he had been a partner since 2004.

He will be succeeded as German litigation head by Frankfurt-based litigation partner Wolf Bussian.

Busse deals exclusively with arbitration, with his work covering all stages of the arbitration process, from initial advice to clients and settlement negotiations up to advocacy during hearings and enforcement, or opposing enforcement, of an award.

His departures follow several moves within A&O's litigation and arbitration practice. Earlier this year, litigation heavyweight and global intellectual property head Nicola Dagg left A&O's London office to join Kirkland & Ellis' City base, while in 2017 arbitration partner Jeffrey Sullivan left A&O to join Gibson Dunn & Crutcher.

A&O said: "We would like to thank Daniel for the contribution that he has made during his time at A&O and wish him all the best for the future."

Separately, A&O has bolstered its London litigation ranks with the hire of partner Suzanne Spears from Volterra Fietta, where she was head of its business and human rights (BHR) practice.

Prior to joining the firm in 2015 as a partner, she was previously a counsel at US firm Wilmer Cutler Pickering Hale and Dorr. Her experience includes advising private clients, governments and international organisations on a wide range of contentious and non-contentious public international law matters.

A&O international arbitration global co-head Mark Levy said: "Combining two very specialist areas of practice, in investment treaty arbitration and BHR, Suzanne will significantly enhance our offering to clients. In her investment treaty practice, Suzanne has represented governments, as well as corporates, with a particular focus on energy and natural resources, which dovetails perfectly with our existing practice. Suzanne also has particular expertise in Latin America and Africa – priority areas for us and an ideal complement to our new South African litigation team."

The moves come amid ongoing merger discussions between A&O and US firm O'Melveny & Myers, which has a strong focus on disputes work. The talks are understood to still be at the due diligence phase.

Legal Week revealed last month that senior figures from both firms had met to discuss the merger in Frankfurt.