For the past two years I've worked with this man, Nigel (not his real name, obviously). Nigel is technically slightly more senior than me but is the most unfortunately incompetent manager I've ever had to work with. I also outrank him in the project on which we collaborate (he's the technical lead for one of two streams and I'm the client facing global delivery manager), which irks Nigel to no end.
Nigel can't be replaced because ... reasons (basically, his boss knows he's useless and wants him on the project because this makes him my problem as opposed to his), which more often than not means I end up having to personally double check and re-do half of his stuff to avoid disaster. His achievements include highlights such as approving simultaneous leave for his entire team in the days before major milestones, misreporting billable hours, having a team member of his work completely illegal hours for months on end, and so on and so forth - you name it, he's screwed it up.
Having had enough after his latest fuck-up, I wrote an (admittedly not very nice but professional throughout - I had someone read it before rage-mailing) e-mail to him CCing both my boss and Nigel's. Here'so what the fuck wad replied:
[lengthy explanation as to why every single member of the team except him is to blame even though it's his work stream that funked up] ... as I have stated on numerous occasions, I am more than happy to take on additional management responsibility for [project] and am still anxiously awaiting an opportunity to do so. I am confident that my skills could be better leveraged given more seniority
Now this is very much not a question of how I defend myself. I'm not being threatened here. Everyone involved (minus himself) gets that Nigel is incompetent, and he's just shown himself to grossly unaware of the fact. But how on earth do I respond, given that this is business and 'oh do fuck off!' Is not an option?