Viruses in TPS&Tomatoes seed ??

[Medbury Gardens]

I would imagine Tom would know the answer to this question,a question which was asked of me by a gardening friend while we were talking about the importation of vegetable seeds,i was asked why is it we can bring in all veg seed other than TPS and tomato seed,i thought it must be that the border control biosecurity people believe that potentially they can carry diseases or viruses,.....how much truth is in that??,or is it more to do with protecting our potato breeding industry.