I'm afraid not; the only HMRC letter I have has a temporary NI number on :/

I have recently been offered a job with a well-known company, but I cannot start induction with them until I provide proof of my national insurance number. They say that ONLY the following count as acceptable proof:

• P45
  
• P46
  
• Former payslip
  
• Letter from HMRC
  

As I have not had any previous contractual jobs, I have no P45 or P46.

However, I DO have a former payslip as well as a letter from HMRC. But the problem is that the National Insurance number on them is only a temporary one, so I cannot use them as proof of my permanent National Insurance number.

So this leads me onto my first question: why do people keep giving me temporary national insurance numbers despite them knowing my permanent one??

I tried to solve this by using HMRC form CA5403 (a request of National Insurance number confirmation) and sending it to HMRC using a first class stamp.

However, reading up on the internet I have read many horror stories of HMRC taking months to get back by post.

So this leads me onto my second question: how long does HMRC take to get back to NI number confirmation requests? I cannot start work until I get a letter from them so they are kinda holding my employment prospect in the balance. Needless to say, I am slightly p*ssed off with it all.

I would be immensely grateful if anyone could answer my questions, thanks in advance!