The BC Liberal party has revoked the party membership of MLA Darryl Plecas, one day after he became Speaker of the provincial legislature.

The party announced that Plecas was no longer a member in a statement on Saturday.

"Constituents must be able to trust their elected representatives," it said. "Party members must be able to trust those who hold positions of leadership in the party. And members of the legislature must be able to trust one another."

The statement said Plecas' decision was a betrayal, one he made "despite repeated promises and assurances that he would not."

Revoking Plecas' membership was "the strongest action available," a spokesperson added.

Liberal MLA Darryl Plecas sits alone in the Legislative Chamber after skipping caucus meeting. He was later named Speaker. (Richard Zussman/CBC News)

'I took him at his word': Coleman

Plecas, MLA for Abbotsford South, was the only member of the legislature to put his name forward for Speaker.

The move strengthened the NDP government's position in the minority parliament, ensuring the party didn't lose a voting MLA to sit as Speaker.

Plecas was also the only member of the BC Liberals to speak out against the leadership of its former leader, Christy Clark.

The party's interim leader, MLA Rich Coleman, didn't mince words about his former colleague's move to the Speaker's chair.

"Everyone had committed, including Mr. Plecas, to not run for Speaker," Coleman said Friday. "I took him at his word. Obviously, that word didn't mean a lot."

There are now 41 Liberals MLAs, 41 NDP MLAs, three Green MLAs as well as Plecas sitting in the legislature. The Speaker would break any tie votes.