MADRID, July 1 (Reuters) - Spain's conservative People's Party is set to win the most seats in the lower house of parliament in a national election next month, ahead of the ruling Socialist Workers' Party (PSOE), a poll released by El Mundo newspaper showed on Saturday. The survey, carried out between June 26 and 30, showed the PP widening its lead over Prime Minister Pedro Sanchez's PSOE, pollster Sigma Dos said. The poll estimated that the PP would get between 140 and 143 seats in the 350-member lower house, up from 140 in the previous poll held between June 16 and 23. The PSOE would get between 102 and 105 seats, it showed, compared with 102 in the previous survey. The far-right Vox party, the PP's likeliest post-election ally, would get 34-36 seats, compared with 35 seats previously.

---

Persons: Pedro Sanchez's, pollster Sigma Dos, Podemos, Sanchez, Jessica Jones, Alex Richardson Organizations: People's Party, Socialist Workers ' Party, PSOE, El Mundo, Pedro Sanchez's PSOE, pollster, Vox, Thomson Locations: MADRID