Olswang City litigation partner Anna Caddick has left the firm to join Facebook as EMEA head of regulatory and litigation.

The commercial litigator first joined Olswang in 2009 as a legal director and was made up to the partnership in 2015 in an all-female promotions round at the firm.

Facebook is a longstanding client of Olswang. The social media giant's deputy general counsel Ashlie Beringer said: "We're thrilled that Anna will be joining us to lead our regulatory and litigation teams in Europe. Her strong litigation skills and leadership will add to the strength of our growing legal team."

An Olswang spokesperson said: "Anna has been a valued partner within our industry-leading commercial litigation team, and so it is with mixed emotions that we bid her farewell from the partnership. However, we are delighted to see her take on this new role with a valued client, we wish her well and we look forward to continuing to work together in the future on our significantly enhanced platform alongside CMS and Nabarro. "

Caddick qualified as a solicitor at legacy Lovells, before training as a barrister at Hogarth Chambers, where she specialised in intellectual property (IP) disputes.

Her exit comes five months after Olswang's partners approved the three-way merger with CMS and Nabarro, which is set to go live this May. The tie-up will create a firm with combined revenues of almost £1bn, including turnover from the global CMS network.

Legal Week reported last October that Olswang had asked its partners to sign a lock-in agreement committing them to the merger deal, with those not agreeing to sign expected to move on before the 1 May go-live date. The lock-in will last from May to October.

Olswang saw a raft of senior London exits last year, including IP partner and co-head of life sciences Stephen Reese, who joined Clifford Chance in October, and restructuring head Alicia Videon, who left to join McDermott Will & Emery just days before the merger was confirmed by management.

Other partner departures towards the end of the year included former Asia head Rob Bratby to Arnold & Porter, patent prosecution co-chair Justin Hill to Dentons, and corporate finance partner Azlinda Ariffin-Boromand to Withers.