However, Ed Miliband mocked what he described as "the same old faces, the same old policies; a no-change reshuffle".
In fierce Commons exchanges, the Labour leader referred to how Chancellor George Osborne was booed during the London Games. "The Paralympic crowd," Mr Miliband told MPs, "spoke for Britain."
He rubbished the Coalition's record on infrastructure, saying none of the roads announced in its "grand infrastructure plan" had started and house-building was down since it came to power in 2010.
Mr Cameron hit back, saying housing starts were up one-third since 2009 and seizing on how Britain had moved up the world rankings for competitiveness.
He decried what he called Labour's only answer to the economic crisis – "spend more, borrow more and put up the debt".
Later, addressing the 32 colleagues, who are full-time Cabinet members or who can attend Cabinet, the Prime Minister insisted everyone in the Coalition was now involved in the mission to cut the deficit and get the economy moving again.
"This is a huge effort for right across Government and it absolutely has got to have as much pace and effort and energy as we can possibly muster," declared Mr Cameron.
He added: "It is the biggest challenge that we face in our country, dealing with these twin threats of deficit and growth."
Downing Street said a new Cabinet body, the Growth Implementation Committee, would be established with the sole purpose of making sure Government policy is implemented.
It will be chaired monthly by the Chancellor and aims to drive forward measures, cut red tape, streamline planning rules and get big infrastructure projects moving.
Today, the Coalition will unveil a package of planning and housing measures aimed at "getting Britain building".
One, to sweep away the red tape that prevents families and businesses from making improvements to their properties, will apply only to England but proposed new help to thousands of first-time buyers onto the property ladder will cover the whole of the UK.
As No 10 confirmed that a total of 30 ministers had "resigned" in the reshuffle, it emerged last night that Lord Ashcroft, the Conservative peer who has donated millions of pounds to the Tories, had been appointed the PM's Veterans Czar.
The former deputy chairman of the Conservative Party, who has spent his life building the world's biggest collection of Victoria Cross medals, was said to have had "a long-standing and deep interest in the Armed Forces and a track record of support for veterans".
Downing Street also announced Sir George Young, the former Commons Leader, is to become a Companion of Honour, while four departing ministers will get knighthoods.
In the political fall-out from the reshuffle, Tory backbencher Rob Wilson claimed it was "part of the process of divorce with the Liberal Democrats".
Nick Clegg, meantime, denied the promotion of Tory traditionalists meant a lurch to the right for the Coalition.
"Right from day one, this Government was anchored in the centre ground," insisted the Deputy Prime Minister.
"We've got a Coalition agreement which ... is a tablet of stone, setting out what we are going to do; that is not going to change," he added.
However, Tim Farron, the LibDem president, openly voiced concerns, saying: "If we have got Conservative ministers who want to do more right-wing, reactionary things, it shows the Liberal Democrats are all the more important in stopping them."
Elsewhere, the drama of the reshuffle included a claim that three Tory ministers, thought to include Caroline Spelman and Cheryl Gillan, respectively the ex-Secretaries of State for the Environment and Wales, broke down in tears when they were sacked by Mr Cameron.
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