The Conservative Party must inspire a new generation to reject the "fundamentalism of socialism", International Trade Secretary Liam Fox is set to urge.

In a speech to the Centre for Policy Studies on Thursday evening amid the Tory leadership race, Dr Fox will call on the party to speak for the "quiet Conservatives" who are "all around us".

The Cabinet minister, who is supporting Foreign Secretary Jeremy Hunt to be the next prime minister, will tell the centre-right think tank: "We Conservatives treat people as they are, not as we would like them to be.

"We understand the motivations and the dreams of our fellow citizens - enhancing their freedom, but yes, requiring responsibility; maximising choice and therefore competition; and appealing to a belief in the possibility of one's own success.

"These aren't merely the ideals of a political ideology, but the fundamentals of human instinct."

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He will continue: "It is our duty to make this case once again, to inspire a new generation to reject the fundamentalism of socialism, and restore faith in the philosophy of opportunity.

"Let us speak for those quiet Conservatives - for they are all around us - and ensure that our place in the next chapter of our nation's history is sealed.

"Not for our own benefit, but for the prosperity, security and opportunity that the people of our United Kingdom deserve to have."

Dr Fox will say the Tories have been the "most successful democratic party in the Western world, and the natural party of government in the United Kingdom for well over a century".

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And he will add: "Perhaps it is prudent, even necessary, to have such periodic heart-searching, but it is no excuse for the sort of self-induced negativity that occasionally afflicts British conservatism.

"Today, as we embark on the leadership contest that will select a new prime minister, we need to remember some of the fundamental benefits the Conservative Government has delivered, like record levels of employment, rising living standards, record levels of exports and foreign investment pouring into the UK."