Yup - used to wear them too - had a black and a brown pair both from M&S. And they were really slimming - had no bulky pockets/zip etc so T-shirts just skimmed! They really weren't as hideous as they sound (honest guv)- they weren't for training in they were proper trousers (if we are talking about the same thing)
Haven't seen any about for a while mind
Good luck with the hunt!
Carol x