Simplify the following text for a Grade 8 native English-speaking person.
Original: His third period as Prime Minister was during the crisis of the Great Depression when he formed a `` National Government '' in which a majority of MPs were from the British Conservative Party and was expelled from the Labor Party .
Simplified: In 1931 , he formed a National Government in which a majority of MPs were from the Conservatives . As a result , he was expelled from the Labor Party , which accused him of `` betrayal '' .