I am prepared to be told IABU 
My 3 DC all attend the same primary school and it seems that the reception TA takes the class by herself on a friday, and my yr 4 DS says that a TA takes his class on a fri afternoon. This TA is one of the mums from his class, she has only been a TA for a year. I find it hard to believe she could have done enough training to manage a class by herself.
I also think that it undermines the teaching profession to use a TA, as AFAIK they have little or no training at all.
So AIBU to think that TA should be just that, teaching assistants?