Latham & Watkins has strengthened its London and New York offices with the hire of Allen & Overy (A&O) US corporate partner Peter Harwich and CMS UK litigator Ian Felstead.

Harwich is leaving A&O's New York office after more than 15 years with the firm, during which time he has worked on high-profile deals including SAP's $3.4bn acquisition of SuccessFactors and IT company CSC's 2015 combination with SRA to create a $5.5bn (£4bn) company.

Meanwhile, in London, former Olswang partner Felstead has joined Latham this week, a full six months after news of his hire first emerged.

He handed in his notice at legacy Olswang before its union with CMS and Nabarro went live in May, but has only just been released from his notice period to join US leader Latham.

He joined Olswang as a trainee in 2000, going on to make partner in 2010. His clients include ITV, while he also acted for News Group Newspapers in relation to the 2011 hacking scandal.

Legal Week previously reported that almost a third of Olswang's partnership left the struggling firm in the financial year before its merger with CMS and Nabarro, In total, 28 partners departed between 1 May 2016 and 30 April 2017, equating to 28% of the firm's total partnership, based on its 2015-16 partner count of 101, according to Companies House records.

Latham declined to comment on Felstead's arrival. However, in a statement on Harwich's hire, New York managing partner Michele Penzer said:  "Peter is a recognised leader in public M&A, and that experience combined with his broad understanding of corporate and securities matters, will be of tremendous value to our clients not only in New York, but across the globe."

News of Harwich's exit from A&O comes after it was confirmed last week that Washington DC partner Heath Tarbert, who led the magic circle firm's US bank regulatory team, is leaving the firm to take up a top post at the US Treasury Department, after the US Senate confirmed his appointment as assistant secretary overseeing international markets and development.

However, this August A&O continued to build up its New York office with the hire of Ashurst finance partner Lawrence Berkovich, who became the ninth partner addition the firm has made in New York in just over a year.