David Cameron and Nick Clegg will insist the coalition is "steadfast and united" as they mark the halfway point in their Government with a raft of pledges on childcare bills, infrastructure investment and help towards care costs for the elderly.

The Prime Minister and Deputy Prime Minister will make a rare joint appearance where, in an echo of the now infamous rose garden press conference that launched the power-sharing Government, they will set their new priorities for the next two-and-a-half years.

They will insist their sense of shared purpose on the big issues has "grown over time" as they publish a mid-term review that looks back at how successful the Government has been in meeting its coalition agreement promises and commits them to further reforms.

In a joint forword to the report, the PM and Deputy Prime Minister wrote: "We are dealing with the deficit, rebuilding the economy, reforming welfare and education and supporting hard-working families through tough times. And on all of these key aims, our parties, after 32 months of coalition, remain steadfast and united.

"Of course there have been some issues on which we have not seen eye to eye, and no doubt there will be more. That is the nature of coalition. But on the things that matter most - the big structural reforms needed to secure our country's long-term future - our resolve and sense of shared purpose have, if anything, grown over time."

The review, which aides insist is not a relaunch, promises to help families with their childcare costs amid speculation working parents with children under five will receive financial support.

It also pledges to "provide dignity in old age" with an improved state pension and help towards the cost of long term care. That follows a review by economist Andrew Dilnot, which recommended setting a care bill limit of between £25,000 and £50,000 to stop pensioners being forced to sell their homes to cover costs but the Government has looked at a number of options, including a £75,000 limit.

The joint forword states: "Today, at the half-way point in this parliament, we are taking stock of the progress we have made in implementing the coalition agreement that we signed in May 2010. But we are also initiating a new set of reforms, building on those already under way, to secure our country's future and help people realise their ambitions.

"We will support working families with their childcare costs. We will build more houses and make the dream of home ownership a reality for more people. We will set out plans for long-term investment in Britain's transport infrastructure. We will set out two big reforms to provide dignity in old age: an improved state pension that rewards saving, and more help with the costs of long-term care.

"And as we take these steps to reshape the British state for the 21st century, we will take further steps to limit its scope and extend our freedoms. We will be making announcements about each of these policy initiatives in due course."