Buggerance Factor
Buggerance Factor: This is derived from the English slang buggerance meaning an annoyance, an untimely interruption or something else that interferes with the smooth progress of work. Its use became particularly prevalent in project management where it became necessary to allow additional time for these unforseen and unforseeable events. Where it was not possible to allow this time against a particular element of the project, a non-specific increase in time was allowed to cover these eventualities which became known as the Buggerance Factor.

The Buggerance Factor is there to cover the extra time needed to rectify those things, which never ever go wrong, but invariably do if you fail to allow for them. It is usually added because of a sixth sense on the part of the project manager that something unexpected is going to happen and is the factor that allows for the law of project management that states Parkinson, Murphy and Sod are alive and well and working on your project.
Malcolm's managed to wangle his way on to the next project!
That fuckwit! We'd better increase the buggerance factor in that case.