my nephew lost his job in march and has been on jsa since, has now prospect of another job but would he have to get p45 from jobcentre or would he still use the one he got from employer in march
He'll need the P45 from the job centre. They can take a few weeks to arrive though, so he may have to fill in the other form (p46?) to say he has no p45 at the moment. Then when the P45 does come he should give that to his employer.
Using the p45 from his previous employer will only cause confusion I feel and may give HMRC tthe impression he is trying not to declare his JSA
Just to clarify, when i said "get the p45 from the job centre" I was just using your terminology. In practice it comes from a DWP processing centre.
When he signs off it's worth asking them to send the P45 as a matter of urgency.
I'll warn you though that in my experience the DWP P45s can be unreliable- for mine they left half the required boxes unfilled