The deal means no compulsory redundancies for three months. But it applies only to the 30,000 jobs at risk within Mr Johnson's department and not to the eventual cut of 100,000 jobs across the civil service which the chancellor, Gordon Brown, has proposed.
Nor does it remove the threat of redundancies or of renewed industrial action by members of the Public and Commercial Services Union (PCS), whose action shut benefit offices, driving test centres and museums on November 5.
After talks with Mr Johnson and Brendan Barber, the head of the TUC, Mark Serwotka, general secretary of the PCS, warned that services might still be "decimated" but said his union had won "significant concessions".
Whitehall officials said that Mr Johnson, a former union leader, had "rolled his sleeves up" to sort out a step-by-step process to reconcile conflicting interests.
With the shadow chancellor, Oliver Letwin, taunting Mr Brown about rising staff numbers in Whitehall - despite his promised cuts - Mr Johnson regards his agreement as a beacon for other departments.
However, Mr Serwotka said the fear is that for many the agreement will merely be a "stay of execution".
