Liberal Democrat leader Sir Vince Cable has called for wealth taxes, as he insisted his party is not just "Ukip in reverse", caring only about Brexit.
Sir Vince used his first keynote address to the Lib Dem conference as leader to urge a crackdown on property speculators to ease housing problems.
The Lib Dem leader said he wanted to see the tax system shift to imposing levies on wealth accumulated through property and savings, rather than work.
He told delegates: "We must end the stranglehold of oligarchs and speculators in our housing market.
"I want to see fierce tax penalties on the acquisition of property for investment purposes, by overseas investors."
Despite insisting there is more to the Lib Dems than opposing Brexit, Sir Vince said EU withdrawal ranked alongside the Iraq War and the banking crisis as one of the "three great disasters" to hit Britain in recent years.
Sir Vince accused ministers of behaving like dictators over Brexit as he called for "political adults" in Tory and Labour ranks to join forces with him and try to reverse withdrawal from the EU.
He challenged Foreign Secretary Boris Johnson and other Brexiteers to defend any deal hammered out with Brussels in a new referendum.
The Lib Dem leader labelled Brexiteers "masochists", saying: "What are they afraid of? They now believe in the slogan of dictators everywhere: 'one person, one vote, once'.
"We believe the public have a right to change their mind.
"At the end of these tortuous divorce negotiations, the British public must be given a vote on the outcome."
Sir Vince called for a cross-party effort against a hard Brexit.
He said: "What the country now desperately needs is some political adults. There are sensible grown-ups in the Conservative Party, and the Labour Party and the Greens."
Sir Vince said that the sharp drop in the pound since the referendum is a taste of things to come.
The Lib Dem leader used the address to demand that Prime Minister Theresa May guarantees the rights of EU nationals in the UK
Sir Vince accused Labour leader Jeremy Corbyn of trying to face both ways on Brexit.
The Lib Dem leader compared Cabinet differences on Brexit with a public school pillow fight.
"A disaster looms - Brexit. The product of a fraudulent and frivolous campaign led by two groups of silly public school boys reliving their dormitory pillow fights."
Taking a swipe at US President Donald Trump, Sir Vince said it was "unforgivable" the Government was entrusting Britain's standing in the world "to a special relationship with a president who is volatile, dangerous, and an apologist for religious and racial hatred".
Sir Vince also called for a clampdown on "the blight" of absentee second home owners in rural communities.
Acknowledging the Lib Dem U-turn on tuition fees that badly damaged the party's standing, Sir Vince said he wanted to create an "endowment or learning account" to help people access higher education at any time of life.