Sir Nigel Knowles is stepping down as global co-chairman of international firm DLA Piper and will retire as its senior partner at the end of April, the firm today announced.

Knowles (pictured), who has been at the firm for almost 40 years, will also retire as a partner at the end of June. He will remain on as a consultant.

Simon Levine, global co-ceo at DLA Piper, said:The contribution that Nigel has made to the firm is immeasurable. His vision and leadership over nearly 20 years has played a huge part in the creation of DLA Piper, taking the firm from six UK offices to the global firm it is today.

‘We are all extremely proud of everything Nigel has achieved and are very pleased that he will continue to have a very close relationship with the firm.’

The election process to find a new senior partner will start immediately. The firm says a new senior partner will be selected by the end of March, and appointed at the start of May.

The international board will then nominate the successful candidate as the global co-chair.

Knowles described the creation of DLA Piper as his ‘proudest achievement’, but added: ‘Now is the right time for me to stand down safe in the knowledge that I am leaving the firm in very capable hands.’

Knowles was the global co-ceo and managing partner at the firm for nearly 20 years before becoming global co-chair at the start of last year. He was knighted in 2009 in recognition of his services to the legal industry.

While at the firm he played an instrumental role in the merger between DLA, US-based Piper Rudnick and Gray Cary Ware & Freidenrich LLP in 2005.