The UK Liberal Democrat leader will accuse his Tory coalition partners of being unable to stand up for Scottish interests in a conference speech.
Nick Clegg, appearing before Scottish Lib Dems in Dundee, will draw attention to the backlash his party suffered for agreeing to join the UK Government at the last general election.
"I know that the fact of going into coalition with the Conservatives has been particularly controversial in Scotland," he is expected to say.
"The legacy of Margaret Thatcher's Government lingers long in the memory. People in Scotland know that the Conservatives cannot be trusted to deliver a fairer society. Not on their own anyway.
"With only one MP in Scotland, who honestly thinks that the Conservatives on their own will stand up for you?"
The Lib Dems have 11 MPs in Scotland, including Scottish Secretary Michael Moore and Chief Treasury Secretary Danny Alexander. The only Tory MP, David Mundell, is a minister in the Scotland Office. The Lib Dems at Holyrood were reduced from 16 MSPs to five at the last Scottish election, one year on from the coalition agreement.
Mr Clegg is expected to focus on his plans for a "fairer society" during his speech. He will underline opposition to Home Secretary Theresa May's suggestion that Britain could pull out of the European Convention on Human Rights.
"She wants this option to remain on the table: no chance," he will say. "As I said last weekend, it won't be on the Cabinet table as long as I'm sitting round it. That's why having Liberal Democrats in government, anchoring it in the centre ground and delivering for Scotland, is so important. Building a stronger economy in a fairer society, enabling everyone to get on in life."
But to reach that goal, Scotland must remain in the UK, he will say. "I believe the bonds that bring us together are stronger than the forces that would tear us apart."
Lib Dems will also hear from Mr Cable and the Scottish party leader, Willie Rennie. Mr Alexander will speak to the party on Saturday.