So i got a letter from hmrc (UK tax) letting me know I'm due for a refund, and on one of the bits I need to fill out it asks me for my "Work or Clock number" for each job I've had during the tax year.
I don't know what this is, and googling the term has yielded nothing.
What is it and how do I get hold of it?
The item in question is circled in green. Thanks.
Edit: for those of you saying to be careful and that it looks like a scam, here is the first page and the return address: That address on top (at least the post code) is listed on the UK government website see here.