The Conservative Prime Minister and his Liberal Democrat deputy are at the half-way stage in their Government, which began with a famous joint press conference in the garden of 10 Downing Street in May 2010.

The pair will make fresh pledges on transport and housing infrastructure investment, childcare bills and help towards care costs for the elderly.

These will have little direct relevance to Scotland, and in the trailed foreword of their mid-term review last night there was no mention of the forthcoming independence referendum.

Instead, the joint document reflects on a difficult two-and- a-half years and promises to proceed in coalition "steadfast and united," particularly on deficit reduction.

Mr Cameron and Mr Clegg write: "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."

They pledge to "reshape the British state for the 21st century" and "take further steps to limit its scope and extend our freedoms," adding: "Our mission is clear: to get Britain living within its means and earning its way in the world once again."

Mr Cameron yesterday told the BBC's Andrew Marr Show that he intended to fight the next General Election as Tory leader and serve a second term as Prime Minister, and in a sop to his Eurosceptic wing he suggested it should be harder for EU migrants to come to the UK and claim benefits.