Tories have a "moral obligation" to end poverty at home and abroad, shadow foreign secretary William Hague says.
Mr Hague said the party had a 'good opportunity' to win power
In a speech to Scottish Tories, he also said Tony Blair had presided over "one of the worst governments in the history of Britain".
Chancellor Gordon Brown had "reduced" living standards, he said.
Mr Hague said party leader David Cameron gave Conservatives the "best opportunity in a long time" to win a general election.
'Disraeli and Macmillan'
Mr Cameron recently said the party should be judged on what it can do for the poorest in society.
He also said he would put economic stability ahead of tax cuts, which has angered some Tories.
Mr Hague said: "When we say that the test of our policies must be whether they help the least well-off and not just the rich, that is something of which Disraeli with his Factory Acts and Harold Macmillan with his house-building programme would have proudly endorsed."
He told the conference in Perth: "I have seen a lot of party leaders and I can tell you that David Cameron is giving us the best opportunity in a long time to win the next general election."
Mr Hague said the Conservative Party had last taken a comprehensive look at its approach to foreign affairs in the 1970s - when Iran was an ally of the West, Zimbabwe was a British colony, and the Warsaw Pact ran eastern Europe.
A Tory foreign policy would include a "solid but not slavish, firm but also fair" relationship with the United States.
Mr Hague said: "Our moral obligation to make poverty history will be reflected in our foreign aid policies, always encouraging property ownership, the rule of law, and allowing markets to make people richer than dictators to ruin their lives."
In his attack on Labour, Mr Hague said the Tories must offer a "real, robust and respected" alternative to Labour.
But International Development Secretary Hilary Benn said: "The best way we can demonstrate our moral responsibility to making poverty history is what we do in government."
Labour had "more than doubled" the UK aid budget since 1997, he added.
Mr Benn said: "Many people will remember that when the Conservatives last had the chance to demonstrate their commitment, they cut Britain's aid budget in half as a proportion of our national wealth."