TORONTO - Speaker Steve Peters is making a final appeal to the governing Liberals to save the Ontario legislature's impressive skyline.

Two high-rise condominium towers are slated for construction behind the 118-year-old building in downtown Toronto -- something Peters says will permanently destroy the legislature's vista.

This week, a court turned down his request to appeal approval of the project by the government-appointed Ontario Municipal Board.

Peters says he has exhausted every avenue to stop the project, and it's now up to Premier Dalton McGuinty's government to save the legislature from encroaching development.

He says he's writing to the government in a last-ditch effort to protect the historic building's skyline.

The opposition parties say the Liberals -- who've refused to intervene so far -- should have stepped in sooner.

Progressive Conservative critic Lisa MacLeod says she's disappointed that the project will go ahead and that the Liberals haven't stopped it.

NDP critic Peter Kormos says the Liberals could have enacted legislation that would have protected the building's skyline.

Peters first took the unusual step of pushing his own party to halt the planned construction in May.

The New Democrats backed him up and said they would support legislation to save the building and its view.