Protesters from the Bloomsbury Fight Back group have been occupying the building in Gordon Square since 23 November, and have since turned it into a workspace they have dubbed the Bloomsbury Social Centre.
They were served with a possession order yesterday that will come into effect tomorrow morning.
The building had been empty since 2008, but refurbishment to transform it into a research and study space for postgraduate students was due to start on 28 November.
Soas said that the delay in the schedule was costing the institution £4,000 a week.
A spokesman for the occupiers said that the group were expecting “a very physical eviction”, adding that the possession order had come as a shock to the occupiers, who had not considered their dealings with the university to be antagonistic.
He said that the group were happy to negotiate a mutually agreeable time for departure; the occupation has offered 10 January as a potential departure date in order to allow “politically necessary and socially useful” work to be done by the protesters over the Christmas holiday.
“We think we’re doing really critical political work in this area. Not just around students, but also with benefits claimants, the elderly and the unemployed; we feel like we’re doing really good work,” he said.
A spokeswoman for Soas said that postgraduate students as well as representatives of the institution had made “repeated attempts” to communicate with the occupiers to find a resolution.
“We have also reiterated the impact this is having on our students,” she said.
“The majority of people in the building have no links to Soas. At no time prior to legal action being taken did the occupiers respond to communication from Soas. We have been left with no alternative but to pursue a legal resolution.”