Afterwards, Prospect National Secretary David Luxton said: "The chief executive announced that a £500 share allocation would be made to all employees in QinetiQ.

"This was a key demand of Prospect so that all employees would have a stake in the newly floated company, and we welcome it. In addition, there will be a priority offer for staff to purchase additional shares after the flotation date, set for February 15.

"Prospect welcomes the end of the long period of uncertainty that led up to today’s announcement. We want QinetiQ to be a successful publicly quoted company and we wish it well."

Luxton said the union was also pleased that the staff pension scheme would benefit by more than £100m after flotation, with the costs shared between the Ministry of Defence and the Carlyle Group.

Prospect has 3,000 members spread across QinetiQ’s sites, chiefly engineers and scientists.