Olswang technology partner and former Asia head Rob Bratby is set to join Arnold & Porter's London office ahead of the UK firm's planned three-way tie-up with CMS and Nabarro.

Bratby, whose practice focuses on corporate work in the telecoms, media and technology sector, was Olswang's Asia managing partner from 2011 until earlier this year, when he returned to London from Singapore.

He is set to join Arnold & Porter in London early next year, as it prepares for its own merger with fellow US firm Kaye Scholer.

Bratby's exit comes after Legal Week revealed that Olswang's patent prosecution group co-chair Justin Hill is set to join Dentons in London as a partner and head of its European patent prosecution and opposition practice.

Hill was the second Olswang intellectual property (IP) partner to resign from the firm since it emerged that the firm was set to merge with Nabarro and CMS on 1 May  2017. Former Olswang London IP partner and co-head of life sciences Stephen Reese joined Clifford Chance at the start of October.

Legal Week reported last month that Olswang partners had been given until 10 October to sign a lock-in agreement committing them to the union, with those not agreeing to the lock-in expected to leave before the go-live date in May.

Other UK exits since news of the union broke include restructuring head Alicia Videon, who has joined McDermott Will & Emery as a partner in its London transactions practice.

Arnold & Porter confirmed earlier this month that it will go ahead with its merger with New York-headquartered firm Kaye Scholer in January next year, a deal creating a $1bn firm.

Earlier this month, Arnold & Porter announced that white collar crime partner Sean Curran had joined the firm in London, from litigation boutique Guney Clark & Ryan.

The firm also hired Patricio Grane Labat this month from arbitration boutique Volterra Fietta. Labat was previously a counsel at Arnold & Porter between 2009 and 2013. He has joined the firm in London as a partner in the international arbitration practice.

Richard Alexander, the firm's chair, said earlier this week that the London office will be a target for growth following its union with Kaye Scholer.

"A larger office with an enhanced platform will make us more attractive for potential lateral candidates," he said.

The firm has plans to take more office space in London to accommodate its increased headcount once the merger with Kaye Scholer goes live.