Media playback is unsupported on your device Media caption Vince Cable said Lib Dems 'will not be dragged down' by ugly politics

Lib Dem Vince Cable has launched a scathing attack on his Conservative coalition partners, accusing them of "ugly" and "blinkered" politics.

The business secretary told activists the Tories had "reverted to type as the nasty party" and called their election adviser Lynton Crosby a "rottweiler".

It was necessary to work with Tories in the national interest, but the Lib Dems must not be "dragged down", he said.

Earlier, the Lib Dem conference backed the coalition's economic policy.

In a round of early media interviews, Lib Dem leader Nick Clegg had been forced to deny a rift with Mr Cable over economic policy as he urged party members to stick with the two coalition parties' agreed strategy to cut the deficit through spending cuts and tax rises.

And a few hours later, in his keynote speech to the annual conference in Glasgow, Mr Cable began by making clear he supported his party's decision in 2010 to enter coalition with the Tories and to work "constructively and pragmatically" with them.

'Fear over hope'

But attacking Conservative policies on immigration, the economy and Europe, he said their approach was based on the "cynical" calculation that "fear trumps hope" and "competence requires callousness".

Referring to Home Secretary Theresa May's description in 2003 of the Conservatives as the "nasty party", Mr Cable said the Conservatives had spent years trying to be "nice and inclusive" but had "reverted to type".

Without Conservative Party they would still be a 'knit your own tofu pressure group' rather than a responsible party of government Stewart Jackson, Tory MP on Lib Dems

He suggested the Conservatives had scapegoated the unions, benefit claimants and ethnic minorities to achieve their objectives.

"The list of people the Tories disapprove of is even longer than that - public sector workers, especially teachers, the unmarried, people who do not own property," he said.

He added: "We have dog-whistle politics orchestrated by an Australian rottweiler. It is not our kind of politics. It is ugly and we will not be dragged down by it."

While welcoming signs of an economic upturn, Mr Cable warned his party against getting embroiled in a "petty, points-scoring" argument with the Conservatives and Labour about the strength of the recovery and who should take the credit.

'Amber lights'

He said there was no future for the UK as a "low pay, low productivity economy" and warned about unsustainable rises in house prices - suggesting the "invaders" of property speculators, estate agents and bankers "had to be stopped" from causing another crash.

"We have seen it all before and there are already amber lights flashing of history repeating itself. David Cameron says I am a Jeremiah but you will recall from your reading of the Old Testament that Jeremiah was right."

Among a number of policy announcements, Mr Cable said he had launched a consultation on how to tackle abuses in zero hours contracts, particularly where employers do not offer guaranteed hours, but insist that workers do not work for anyone else.

The Office for National Statistics has estimated that around 250,000 workers are on such contracts, which allow employers to hire staff with no guarantee of work - but some estimate the total is much higher.

Mr Cable said he had also asked the Low Pay Commission to carry out a study on what economic conditions would be needed for the minimum wage to rise more quickly than it has in recent years without costing jobs.

'Infantile'

Reacting to Mr Cable's criticism of his party, Conservative MP Stewart Jackson said "trashing" the coalition government that they were a part of made the Lib Dems "look infantile and undermines their pitch" at the next election.

He tweeted: "Lib Dems forget that without Conservative Party they would still be a 'knit your own tofu pressure group' rather than a responsible party of government."

For Labour, shadow business secretary Chuka Umunna tweeted: "Vince Cable attacks his Tory partners in his speech but has voted for all their measures since 2010. Did he think no one would notice?"

The British Chambers of Commerce said Mr Cable should engage employers in a "national conversation" about pay and productivity but argued that zero hours contracts were a "niche" issue that only affected a relatively small number of workers.