The coalition government, two years on: David and Nick plan a second honeymoon

As the prime minister and his deputy "relaunch" their government, Ian Jones assesses the state of the relationship at the heart of the coalition

Nick Clegg and David Cameron give their first joint press conference after the formation of the coalition government in May 2010Rex Features

Side-by-side in the Downing Street garden, they pledged to spend the next five years together.

Gazing alternately into each other's eyes, David and Nick vowed that their relationship would be "strong and stable", to "put aside differences" and "work hand-in-hand".

As the sun shone down and the scent of flowers in full bloom drifted on the gentle spring breeze, it seemed that this was a union born out of happiness, respect and good fortune, and one that would survive whatever obstacles life would place in its way.

That was almost exactly two years ago, on 12 May 2010.

Today, 8 May 2012, David and Nick renewed their vows - but in vastly different circumstances.

Instead of a well-tended garden, the pair spoke from inside a tractor factory.

Instead of warm, spontaneous talk of being "at each other's side" and the "strength and depth" of their liaison, we heard a more steely, familiar recital of platitudes with which nobody would disagree: help for "hard-working families", that the economy can't be fixed "overnight", and that there will be no "let-up" in tough decisions.

It sounded as if the pair were remaining faithful to their coalition vows despite, rather than because, of the circumstances that have pushed them together.

The prime minister challenged the idea that the UK was facing "austerity", preferring instead to dub it "efficiency".

The change in tone, compared with the unqualified optimism of two years ago, reflects the change in fortune the government has experienced.

Mr Cameron, Mr Clegg and their colleagues have been reeling from hundreds of losses in last week's local elections. A sequence of gaffes, fumbles and crises, dating back to the Budget in March, has convulsed the administration and emboldended critics within both parties to speak out.

With sniping from right-wing Tories and left-wing Liberal Democrats filling the airwaves, there is precious sign of the "new politics" that the prime minister trumpeted two years ago - one where "national interest is more important than the party interest, where co-operation wins out over confrontation, where compromise and... civilised grown-up behaviour is not a sign of weakness but a sign of strength."

Yet both parties have no alternative but to carry on. Once it was only the Lib Dems who were bound, helplessly, into the coalition, aware that were they to leave and prompt a general election, they would be battered at the ballot box and lose dozens of MPs.

But now opinion polls suggest both the Tories and the Lib Dems would go down to defeat were an election to be called. Projections based on current voting intentions give Labour a majority of almost 100. Both Mr Cameron and Mr Clegg know they cannot call the whole thing just yet. Their union would be branded a failure. They had, after all, promised "better times ahead". Those times have yet to arrive.

When David and Nick stood together on a noisy factor shopfloor in Essex this afternoon and, before the world's media, pledged to remain faithful and stay together - at least for the remaining three years of this five-year government - proceedings felt more like an update from the frontline than a bulletin from a brave new world.

Their second honeymoon is not going to be anything like their first.

Long gone are the days when the Lib Dem leader could laugh off the cruel taunts of his Conservative allies, and chuckle that coalition government "means swallowing some humble pie, and it means eating some of your words. I can't think of a more excellent diet."

Pretty much the only thing on the menu this time is gruel - for both Mr Clegg and his political partner.