The Prime Minister will address the Conservative Party’s 1922 committee, tomorrow, in another sign of his tough stance on Europe.
Downing Street has also confirmed that Iain Duncan Smith will continue his work making work pay and reforming welfare as Secretary of State for Work and Pensions.
Tina Stowell will be made a full member of the Cabinet, as Leader of the Lords and Lord Privy Seal.
The full reshuffle is expected to happen tomorrow.
Work and Pensions Secretary Iain Duncan Smith suggested today's unemployment figures show the Government's long-term economic plan "is working".
In the week that Universal Credit started its nationwide roll-out, these figures show that a reformed welfare system goes hand in hand with helping people to take advantage of the record number of vacancies available.
The jobs-led recovery is changing people's lives for the better on a daily basis. We are getting people into work, making work pay, and in so doing we are ensuring a better future for Britain.
Iain Duncan Smith has defended the Universal Credit scheme, claiming it is under budget and helping people find work quicker and earn more.
The flagship scheme - which merges existing income-based benefits such as Jobseekers Allowance (JSA) and tax credits into a single payment - is due to be rolled out across the country tomorrow.
The Work and Pensions Secretary denied claims the flagship scheme was over budget, insisting his department was spending £600 million less on the programme than expected.
Speaking on the BBC's Andrew Marr Show, he said Government research showed that those receiving the benefit were 5% more likely to find employment within four months than comparable JSA claimants.
Labour said the scheme was massively behind schedule and saving far less than expected, describing the roll-out as a "spiralling waste and delays".
Work Secretary Iain Duncan Smith has said he plans to trial pre-paid cards for some benefits claimants:
Work Secretary Iain Duncan Smith has said that the government will accelerate the delivery of Universal Credit from next year, rolling it out across the country in 2015-16.
"I promise you we are going to finish what we started," he told delegates at the Conservative party conference.
Work and Pensions Secretary Iain Duncan Smith has said he supports the Government's position against military involvement in Iraq.
He told Deputy Political Editor Chris Ship that we face "very different circumstances" than during the Iraq War, of which he was a strong supporter.
The Government's Universal Credit programme will roll out across more JobCentres from the beginning of next week.
The new payment, which combines six means-tested benefits and tax credits into one benefit, will be expanded across the north-west of England.
The latest figures show that up to March of this year, 6,550 people had claimed Universal Credit.
The BBC is systematically “downgrading” David Cameron’s pledge to hold a referendum on Britain’s membership of the European Union, leaving most voters ignorant of the Prime Minister’s radical plans, Iain Duncan Smith has said. In an interview with the Sunday Telegraph, he added:
The broadcaster's executives take the view that "we've done that" and the policy does not need explaining.
The British people use the BBC more than anything else to find out what's going on in politics. When was the last time you really heard this?
David Cameron knows he must deliver "significant return of powers" from the EU to win the support of Tory colleagues in a referendum on British membership, Iain Duncan Smith has indicated.
The Work and Pensions Secretary said the Prime Minister was clear he could not "come back with nothing" from a mooted renegotiation after the general election.
He also lashed out at the BBC for failing to give enough prominence to Mr Cameron's promise of an in-out vote in 2017.
Speaking to the Sunday Telegraph, Mr Duncan Smith said: "I don't think the Prime Minister in any way is lost on that fact that he will need to get back some substantial and significant return of powers".
Iain Duncan Smith's universal credit scheme has been given a unique classification in an annual progress report issued by the Government.
Although many of the projects are listed as being "exempt" from publishing a green, red or amber risk (most citing the Freedom of Information Act as the reason), the universal credit scheme is the only one to be listed as "Reset".
During 2013, the Programme was reset, culminating in the revised plans announced on 5 December 2013.
The lack of transparency was highlighted by The Independent, which claimed the Major Project Authority had rated universal credit as “red”, signifying that it is “unachievable within reasonable timescales and to a reasonable budget without urgent remedial action”.