Freshfields Bruckhaus Deringer has signed a 20-year lease for a new London headquarters at 100 Bishopsgate.

The magic circle firm, which has been based on Fleet Street since 1989, will move to its new offices in the summer of 2021.

The firm has signed a pre-let agreement with developer Brookfield Property Partners to occupy 255,000 sq ft across floors 20-32 of the 37-storey tower. Construction of the 950,000 sq ft office and retail development started in 2015 and is expected to finish in 2018.

The move will be a downsize for the firm in London, with its current Fleet Street offices occupying a reported 370,000 sq ft.

The firm has been on a cost-cutting drive in recent years, launching a base in Manchester in 2015 to cover back-office functions and handle some low cost legal work. It is set to move to a new location in Manchester in 2017, with 80,000 sq ft of offices at One New Bailey giving the firm space for 700 employees.

Freshfields London managing partner Julian Long said: "100 Bishopsgate offers a location and the facilities we need to deliver exceptional service to our clients. We have based our choice firmly on what our clients will want from us and on finding the best environment for our people to deliver to clients."

The firm has an option to expand or contract the amount of space it takes prior to occupancy.

Long added: "We have included some flexibility to ensure we can respond effectively to client demands well into the future."

The news comes after Freshfields offered voluntary redundancy to all 180 of its London secretarial staff at the end of last year. The firm is not planning to make any compulsory redundancies, although the process is expected to result in a reduction in overall secretarial headcount.