Right-wing Conservative MPs have published a list of policies they want the next leader of the party to adopt.
Edward Leigh called for 'searching questions' on policy
The Cornerstone Group is calling for a flat income tax rate of 22%, a renegotiation of EU membership and the repeal of the Human Rights Act.
One member - Edward Leigh, who is thought likely to run for leader - said the contest so far had been "dull" and marked by "vague aspirations".
Shadow culture secretary Theresa May says the race has been too "macho".
Mrs May told the Epolitix website: "Obviously it has been predominately male and a bit macho, even though I've been saying things within the context of this as well.
"That's why I talk such a lot about building a more representative party, and having to look and sound more like modern Britain."
Mr Leigh's aides say it is likely he will enter the leadership race.
In its mini-manifesto, the Cornerstone Group, which has around 25 MPs as members, says a flat tax of 22% would cut the tax bill by £40bn, helping "millions of low-paid workers and pensioners".
There would be no tax at all on the first £10,000 of people's earnings.
It calls for education vouchers to be introduced, with schools competing to attract pupils.
The pamphlet also advocates a restructuring of the NHS so that hospitals are no longer owned and run by the state.
The Conservative Party should argue for a withdrawal from the European Convention on Human Rights, it adds.
Mr Leigh said it was "time to articulate a clear set of principles based on fighting political correctness and over-regulation".
There was need for "a radical social agenda to rebuild traditional family life, as well as encouraging people to save for their retirement".
Mr Leigh added: "This has been a dull campaign. We need much more explanation of policies, and how they are going to get us out of the hole we are in.
"We want to ask searching questions about how efficiency gains and tax cuts are going to be made, and what credible radical policies other candidates have to reform the creaking welfare state, that ageing child of Attlee's highly regulated post-war Britain."
The Conservative Party's new leader will be declared by 6 December after a vote open to all the members in the country.
But first the field must be narrowed to two by MPs.
Those who have so far declared their intention to stand are Sir Malcolm Rifkind, Kenneth Clarke, Liam Fox, David Davis and David Cameron.
Mr Davis has called for an end to the "outdated" annual party conference, according to a source close to his leadership campaign.
He is said to favour twice-yearly "political mini-breaks", in "modern" venues, rather than seaside resorts.
Stretching over weekends, these would be easier and more enjoyable for members with families to attend, the source said.