Which department at HMRC do I need to contact to ask for my year work history?

I need to ask the Inland revenue for my work history so my new employer can do check. I have been self employed and unemployed as well as p.a,y.e and I have lost a lot of my info in a small flood.I know the benefits office can inform me of my exact dates of being unemployed but I am at loss to work out which number to ring at HMRC and there just does not seem to be one for general enquiries. Any help gratefully received