Former Ontario premier Dalton McGuinty will resign his seat as MPP for Ottawa-South on Wednesday, CTV Ottawa has learned.

The former premier served as the representative for Ottawa South for 23 years, and held the province’s top job for nearly a decade.

McGuinty stepped down as premier and prorogued the Legislature last October, saying his minority government and the opposition had hit an impasse over issues such as public sector wage freezes.

But the move also postponed hearings into the controversial cancelling of two gas plants during the last provincial election. It also killed a contempt motion against then-Energy Minister Chris Bentley over the gas-plant affair.

When hearings resumed this spring, Ontarians learned that the cost of cancelling and moving the projects is pegged at more than $500 million, well above the figure the Liberals had been touting.

The Ontario Provincial Police have also opened a criminal investigation into the mass deletion of emails relating to the gas plant affair by senior Liberals.

When he prorogued the Legislature, McGuinty said that he would stay on as MPP until the next election, which could have been this spring if the Liberals could not secure opposition support for their latest budget.

However, the Liberal government under Premier Kathleen Wynne, who won the party leadership in January, met enough of the demands made by NDP Leader Andrea Horwath to secure her party’s support.

On Tuesday, the budget passed its final hurdle in the legislature by a vote of 64 to 36.

CTV Ottawa’s John Crupi reported Tuesday that the Ontario Liberal Party will hold a nomination meeting on June 20.