The reasons given are that Warsi could no longer stand the hatred and nastiness she encountered in the Catholic Church. However, as far as we know she has never even met Fr Thomas Rosica, so it is not clear what the problem was.
"I'm not a turncoat," insists Baroness Warsi.
The most remarkable aspect of this defection is that - as with her high-profile "defection" on the Brexit referendum - nobody had the faintest idea that she was ever on the other side.
LATE NEWS: Baroness Warsi has spoken out again, saying, "From now on I identify as a woman, and anyone who refers to me as 'Fred Warsi' is guilty of a transphobic hate crime." The mother-of-one has made it clear that she is does not wish to be regarded as a member of the racist, xenophobic, nasty, male sex. In this case, we are happy to go along with her wishes.
"Don't worry, he only attacks Catholics."
In other news, the Pope has "defected" to the Catholic Church.