Poland’s governing coalition fell apart on Thursday as the conservative Law and Justice party broke with the smaller, populist Self-Defence party over personal and budgetary issues, making new elections likely.

Jaroslaw Kaczynski, the prime minister, said he would request that his twin brother Lech, Poland’s president, dismiss Andrzej Lepper, the leader of Self-Defence as well as deputy prime minister and agriculture minister, calling Mr Lepper a “lout” and saying that it was no longer possible to work with him.