Simmons & Simmons is set to begin its nomination process for senior partner this month, after Janet Gaymer announced her resignation in December.
Gaymer will step down this year to take up a new role as Commissioner for Public Appointments in England and Wales after 35 years at the firm.
A number of candidates are expected to throw their hats into the ring following the nomination period, with the election due to take place before March.
Sources have predicted three front-runners, including managing partner for Italy and former financial services head Richard Slater. Finance litigation head Jonathan Kelly and capital markets leader Jeremy Hoyland have also been touted as possible candidates.
Gaymer will leave Simmons after serving one term as senior partner.
She told The Lawyer: "I made it very clear to the partnership that I would only fulfil one term as senior partner of the firm and no more.
"I won't leave until a new person has been elected to the post, which I expect will happen in February or March."
In her role as commissioner, Gaymer will regulate, monitor, report and advise on appointments made by UK ministers and by the National Assembly of Wales for the boards of around 900 national and regional bodies.
The appointment was made by the Queen and is independent of the Government.
Prior to being appointed senior partner in 2001, Gaymer was the head of the firm's employment law department.
Simmons managing partner Mark Dawkins said Gaymer broke a "glass ceiling" in becoming one of the first female senior partners of a City law firm.