The Mrs was working in BFG doing YTS for the padbrats. There was a constant whinge that they used to get paid less than the similar grade Germans. The excuse given was that their wages were paid net of the monies that would be paid to them and would then have been deducted as NI contributions. We called BS several times.
Anyway, last year, nearly 20 + years later she was finally accredited with the NI contributions as paid up for the period in question.