The project will not be awarded until main building contractor Laing O’Rourke signs practical completion with developer British Land on the 48-floor building as expected in May.
Morgan Sindall’s fit-out arm is battling with Como and ISG to work for anchor tenant insurance giant AON on the lower third of the tapering 122 Leadenhall street tower.
The insurer is planning to take 10 floors, representing 191,000 sq ft of the 224m tall building as its new headquarters.
It also has an option to lease a further 85,000 sq ft across four more floors of the development.
Neither party would comment on contract negotiations for the fit-out job, which is estimated to be worth up to £20m.