Public support for Thai Prime Minister Anutin Charnvirakul and his Bhumjaithai Party has plunged, according to a survey by the National Institute of Development Administration. Only 13.8% backed Anutin in September, down from 21.7% in June. Bhumjaithai’s rating fell to 12.1% from 17%, pushing it into third place behind the opposition People’s Party and coalition partner Pheu Thai.

The decline comes as higher global energy costs squeeze households, with oil prices above $100 a barrel. Anutin’s government faces its biggest political test when the Constitutional Court rules on a challenge to the validity of the February election. Opposition leader Natthaphong Ruengpanyawut remained the most popular PM choice at 24.7%, down from 26.1%.

The People’s Party led party preferences at 35.4%, followed by Pheu Thai at 18.4%.