Orrick Herrington & Sutcliffe's London office has signed up to move into new premises in the City, with the firm also completing its conversion to a UK Limited Liability Partnership (LLP).

The US firm, which launched in the City in 1998, has signed a lease to move its London headquarters to 107 Cheapside from Tower 42, Old Broad Street. The firm is leasing 44,500sq ft in the new development, with an option to take a further 20,000sq ft. The office move is expected to be completed by the end of this year.

Separately, the firm has also set up as a UK LLP, with the structure also incorporating the Paris and Italian arms of the US firm. The firm's other European operations in Germany and Moscow already work under separate LLPs. London managing partner Martin Barlam said the decision was intended to help integrate the European business better.

Orrick has been pursuing an aggressive expansion strategy in recent years, bringing in seven partners in London alone in 2008, with the firm taking on around 80 partners globally over the same period.

Commenting on the London office move, Bartlam said: "This is a significant move for the firm in London and provides a fantastic opportunity for expansion of the London platform. We are excited about the move which will put us in the heart of this redevelopment area of the city in a prestigious and modern space ideal for our clients and staff."