Taking the soup

can anyone elaborate on the meaning of, 'taking the soup',
please.

I am led to believe that it was a way of getting hungry Irish immigrants in england, to drop the mac or o', from their surname. In return for food (soup).

many thanks in advance.

I googled your phrase and found many sites attesting to your theory, one of which is linked below.

It's the same basis for the saying 'you're in the soup' meaning that your choice is either unpleasant or very unpleasant.