Spain’s leading opposition party is set to hand Prime Minister Pedro Sanchez a scathing defeat in a national election next month, according to a new opinion poll.

The People’s Party would win 154 seats in parliament and would be able to form a majority in the 350-member house by joining with far-right Vox, who stand to have 40 seats, according to a survey by polling firm Metroscopia. Sanchez’s Socialist party would win 97 seats.

The poll also shows that Sanchez would be unable to retain his job even if a group of far-left parties run on a single ticket on July 23. Sanchez needs support from the far-left to form a government because his Socialist party is unlikely to reach a majority by itself. Because Spain’s electoral system rewards larger parties more than smaller ones, the far-left groups can win more seats if they run together.

“A single candidacy of the parties to the left of the Socialists would not be enough to avoid a majority of the PP and Vox,” according to the Metroscopia report, which didn’t detail the number of seats the far left could obtain if it runs on a single ticket. The report was distributed to corporate clients.

Parties have until the end of Friday to form their tickets and the two main far-left groups, Sumar and Podemos, are holding last minute discussions to seek an agreement. Leaders of both groups currently serve in Sanchez’s coalition government.

Metroscopia polled 3,000 people over the phone between May 29 and June 7, with a margin of error of 2.3.