UCL wants to transfer 94 estates and facilities staff to private firms, with an additional 14 made redundant and 20 new posts created. It is now considering feedback from a consultation on the move.
The plans would outsource the remaining 30 per cent of cleaning and waste services and 50 per cent of security currently provided in-house. The rest is already private.
UCL Unison says in its response that "many of UCL's lowest-paid staff will effectively have had their pay cut through the loss of their pensions". It also argues that the university has not conducted a proper equality impact assessment.
Of the 65 cleaning staff who would be transferred to private employ, 93 per cent are from black and minority-ethnic backgrounds.
The Unison response, from branch secretary Bill Lehm, says that outsourcing "in the way that is proposed is potentially illegal".
A UCL spokesman described the current mix of in-house and outsourced provision as "inefficient".
"In-house staff terms and conditions will be protected in accordance with Transfer of Undertakings (Protection of Employment) regulations," he said. "UCL is also committed to implementing the London Living Wage for all staff, whether in-house or outsourced, and is working to deliver this."
The London Living Wage is £8.30 an hour.