Clifford Chance (CC) and CMS have advised on the pre-let of 70 St Mary Axe to US law firm Sidley Austin, which is set to move its City operations into the 'Can of Ham' tower.

Sidley will occupy the top eight floors of the building, taking up approximately 100,000 sq ft of office space, when it moves into the new skyscraper in early 2020.

The US firm has also taken options on an additional 34,000 sq ft of space in the building – which is due to open next year – giving it scope for future London expansion.

Sidley currently occupies 85,000 sq ft of space at its current London base at 25 Basinghall Street.

CC advised TH Real Estate on behalf of the Cityhold Office Partnership (CHOP), with a team led by real estate partner Mark Payne, alongside fellow real estate partner Ian Painter, UK real estate construction head Marianne Toghill, head of environment and planning Nigel Howorth and real estate tax head David Saleh.

Payne said: "We have been working on this project with TH Real Estate for a number of years and are delighted to have helped them to put arrangements in place to secure a tenant for this new iconic building. This was a complex multidisciplinary transaction that plays to our strength as a real estate practice focused on the complex and high-value end of the market."

City-based CMS real estate partner Tanya Holt advised Sidley Austin as the lead partner on the move.

Knight Frank acted as Sidley Austin's property consultant on the move, while US professional services and investment management company Jones Lang LaSalle and British real estate professional services company BH2 advised TH Real Estate, alongside CC.

Sidley began searching for a new office in 2017, and the firm is expected to move premises at the beginning of 2020.

Recent London hires for Sidley include corporate partner James Wood, who joined from Freshfields Bruckhaus Deringer, while the firm also launched a London life sciences practice earlier this year with the hire of partner Maria Isabel Manley from Bristows.