How do political parties came to know which MP has voted for what in 22 july voting when it was secret ballot?

Question

on 23rd it was in news one was beated by his paetymen for voting against the party...how do they came to know about his vote status..

Answer 1

No one can tell that who voted for whom, cameras may be installed but cameras cannot focus on the ballet paper to determine the vote.

Answer 2

All MP have to write their detail on there voting slip

Answer 3

i think they don't know but if you think that they know then they probably they have cameras in voting boots