Difference Between the ATS and the MTC

[Home Guard]

I have just started watching season 1 of Foyle's War, as I very much enjoy good English drama TV (of course anything is better than the c##p they air over here). I knew of his driver being army, but had always thought she was ATS, the story taking place in May 1940, but she's not she's MTC.

Now I am trying to understand the difference between the ATS and he MTC? Wondering if I am going to need to add MTC insignia to my ATS collection???

Tried searching here and found some interesting stuff, but no answer to this question. Also Googled it but was unable to find an answer.

Thanks,

Terry