The BT contractor told its 140 staff of the plans at its Basildon office yesterday, according to the Echo News website.
Although Carillion telent reportedly told employees it would try and relocate them to other offices in Cambridge, Croydon and London, workers will have to reapply for the 40 remaining jobs.
Many of the contractors had been previously told that there would be an opportunity to have a permanent job at the firm, according to the Echo.
The job cuts are due to take place over the next six months.
Carillion telent had not responded to a request for comment at the time of writing.
In 2009, the company, a joint venture between support services company Carillion and technology services provider telent, signed a seven-year contract to provide nationwide support services for BT’s Openreach business. It consolidated work that was carried out by seven outsourced suppliers.