In the Republic of Ireland and the United Kingdom, the P45 is the form that a person is handed when leaving a job. The P45 details income for social security purposes. (The two countries' respective P45s are actually different; it's just that the UK and Ireland have very similar administrative processes here.)
Use of the term "P45" depends on context. See the following examples:
to be given your P45 -- to get fired (possibly unceremoniously)
to ask for your P45 -- to quit your job (possibly unceremoniously and/or defiantly)
to be in possession of your P45 -- to be jobless
(The P45 is handed to the employer when starting at the next job.)
An online variant of the P45 form (collected when a person leaves work permanently).
It is used when a person chooses to rescind their friend status with another person.
Alternatively, one may have their friend status rescinded because of behaviour which is deemed unacceptable.
Hey, pick up your E45 you are no longer my e-pal / friend / buddy.
Fuck you, I'm gonna collect my E45, I'm not gonna put up with you Sean.
Acronym: Not Suitable For Work.
Used when posting a link to a site of dubious merit which could cause embarrassment/P45 if linked to while using the Internet at work
Check this out! (note: NSFW)
Link: Ass-fucking pigs
An imaginary reward of an unspecified nature. Often used as a precursor to an attempted stitch up.
"Keep this up bonny lad and I can promise you a place on the board, and all the Air Miles you can eat."
"Oh cheers mate. By the way, whose P45 is that you're filling in?"
See spit roast
Abbreviated in some parts as "P45"
Bubba and Tyrone had Geoffery in Position 45 earlier
An authoritarian figure, usually teachers or bosses at the workplace.
"Shit, I've got maths next with Adolf."
"I can't wait to get my P45 from Tesco, if only to get away from old Adolf over there."
Done to annoy someone who dumps you, as in, ends your relationship.
You order a large skip to be delivered to their house.
"Sarah dumped me last night! I... can't believe it."
"You've got your pint. You've got your pig snacks. What more do you want? C'mon mate, you can skip her in the morning, that'll cheer you up."