Nick Clegg is to draw on Thatcher's legacy to accuse his Tory coalition partners of being untrustworthy in a conference speech on Friday.
Appearing before Scottish Lib Dems in Dundee, 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 Dem leader will argue the government is unable to stand up for Scottish interests and will draw attention to the backlash his party suffered for agreeing to join the UK Government at the last general election.
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 and underline opposition to Home Secretary Theresa May's suggestion that Britain could pull out of the European Convention on Human Rights.
"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.
The UK Lib Dem spring conference was held in Brighton last week in a time of mixed fortunes for the party.
The leadership was given a lift by its triumph in the Eastleigh by-election but forced into damage limitation mode with allegations of sexual harassment by former chief executive Lord Rennard, which he denies.
In Brighton, Lib Dem president Tim Farron cautioned that the party was in a "critical state" and should not assume it had a right to survive.
Mr Clegg was also engaged in bad-tempered clashes with Lib Dem activists over so-called secret courts legislation, a subject that will return at the Scottish conference.
The Justice and Security Bill, which would allow courts to sit in secret in some civil cases, was comfortably given its third reading in the Commons, despite a rebellion from some Tories and Lib Dem MPs and continuing opposition from civil rights campaigners.