Vijz is almost correct. You must be sent the NIP within 14 days (not quite the same thing) or you can be given it verbally at the time. If a prosecution is brought, it must be started within 6 months of the alleged offence.
Not sure which is true.
You Must receive the nip within 14 days
or
They have to issue the nip within 14 days.
It may be possible that someone doesn't receive it until after 14 days of the (alleged) offence.. If the police say they issued it within the 14 days does that mean you can be prosecuted? .. i.e. does their word stand in court against yours?
As they send nip's just normal 1st class mail, and not "signed for" (recorded, registered mail, etc) they cannot prove you received it.
Yes Kev. The police only have to prove that they sent it. The law was changed in 1994. Before that time, the NIP had to be sent by recorded delivery. Now, proof of posting is treated as proof of receipt. I don't know of any way round that - have you ever tried proving that you haven't seen something?