The tough task facing Brown's children

As Sir John Chilcott's Inquiry into the war in Iraq continued to chip away at Tony Blair's historical reputation this week, another of the former Prime Minister's closest allies took his leave of frontline politics.

Amid difficulties in his private life that will surely elicit widespread sympathy, Alan Johnson became the latest in a long line of key players from the Blair Years to depart the political stage.

Looked at in terms of Labour kremlinology, the erstwhile Shadow Chancellor's surprise resignation, and his replacement by Ed Balls, means the Brownite takeover of the party is now all but complete.

Mr Balls, Ed Miliband, Yvette Cooper and Douglas Alexander were all denied Cabinet promotion by Mr Blair – but they now occupy the four most senior roles on the Labour frontbench.

But in this lies the nub of Labour's problem as it seeks to come to terms with opposition and put itself back into credible contention for government.

For as time goes on, it is becoming clearer and clearer that the general election result last May was not just a repudiation of Gordon Brown personally, but of much of what he stood for politically.

There are increasing signs that, like 1979, 2010 could come to be seen as a watershed election, a moment in history which saw a paradigm shift away from the top-down, statist brand of politics with which Mr Brown was associated.

That is certainly the way the Coalition would like us to see it, which is why the proposed reforms to the National Health Service announced this week are so central to its overall political strategy.

The reforms are certainly not without risk for Prime Minister David Cameron. With the possible exception of Coronation Street, the NHS remains Britain's best-loved institution and politicians tinker with it at their peril.

Not the least of Mr Cameron's difficulties, as Alastair Campbell pointed out on Question Time on Thursday night, is that he has no electoral mandate for it.

But the voters tend to be rather less worried about private vs public arguments in public service provision than politicians - and political commentators for that matter – tend to be.

And as long as the service improves in time for the next election – as it may well do once the dust has settled – it could even turn into a vote-winner.

The risk for Labour, on this and other issues, is that it finds itself stranded on the wrong side of a political tide – much as it did in the early 1980s as Margaret Thatcher's free-market revolution forged ahead.

Of all the blows that the Coalition has landed on Mr Miliband since he became Labour leader, none was more telling than Mr Cameron's "I'd rather be a child of Thatcher than a son of Brown."

In truth, Ed Miliband was really only ever an adopted son. The true son of Gordon, the one who was by his side in all his most important decisions, was Mr Balls.

Sure, the combative new Shadow Chancellor will give as good as he gets, but it is already clear that the Coalition will exploit his closeness to the former Prime Minister to the limit.

On the surface, Balls for Johnson looks like a good exchange for Labour – a brilliant economist and pugnacious operator for a Mr Nice Guy who seemed out of his depth in the Treasury brief.

But the whole reason Mr Johnson was appointed to the role in the first place was precisely because he had no economic baggage.

The Coalition's key success since the election has been to pin the blame for the cuts on Labour's mismanagement of the economy and to fix this in the public's mind.

Mr Balls, of all people, is going to have his work cut out to reverse that perception.

Relief for Ed...but just what will David do next?

And so after all the hoo-ha, a relatively easy win for Labour and a creditable second place for the Liberal Democrats, with Nick Clegg's party staving off the post-tuition fees meltdown some had feared.

Both Mr Clegg and Labour's Ed Miliband went into Thursday's Oldham East and Saddleworth by-election on something of a hiding to nothing - but both appear to have got away with it.

Instead, it is Prime Minister David Cameron who may have the most difficult questions to answer after appearing to soft-pedal the party's campaign in the final week.

After their party's share of the vote was more than halved while the Lib Dems' went up, Tory backbenchers already unhappy about the direction of the government will want to know why their coalition partners were given such an easy ride.

For Mr Miliband, a result which saw Labour's majority increase from 103 to 3,558 will take the pressure off – for now.

After a decidedly lacklustre start to his leadership, Mr Miliband moved to sharpen up his press operation in the weeks before Christmas and this appears to have had pretty instantaneous results.

Victory in what was already a Labour-held seat should leave little room for complacency, however.

His appointment of the economically sub-literate Alan Johnson as Shadow Chancellor appears to be unravelling, while his own appearance on a Radio 2 show a couple of weeks back ended in embarrassment, with Middle England listeners quizzing him over his unconventional private life.

The by-election also saw a fleeting return to the political fray for elder brother David Miliband, one of 40 Labour MPs who travelled to the constituency on Thursday for some frantic last-minute door-knocking.

It concluded what to say the least has been an eventful week for the South Shields MP, with his surprise appointment as vice-chairman of Sunderland Football Club.

At the same time, reports emerged that he was being lined-up a possible new role as a TV presenter with the BBC.

Cynics might be tempted to pose the question: What next? An appearance on 'I'm a Celebrity, Get Me Out of Here' maybe?

In fairness to David, he has made clear his intention to continue as a constituency MP at least until the next election, while in an interview with this newspaper before Christmas, he signalled that he has still not given up hope of leading the Labour Party one day.

He has also appeared to set out his stall as a backbench 'Voice of the North' – although his new role at the Stadium of Light scarcely seems designed to endear him to all corners of the region!

But taken together, the two stories highlight the difficulties which can face politicians when they lose their main raison d'etre – climbing the greasy pole.

And while he is not about to join the 'Z-list' of those who are famous for being famous, Mr Miliband needs to give careful thought to what he does next if he is to remain a serious political player.

The prospect of him becoming a TV presenter inevitably drew comparisons with Michael Portillo – and not for the first time.

Mr Miliband's somewhat cack-handed attempts to unseat Gordon Brown in autumn 2008 echoed Mr Portillo's botched coup against John Major in the summer of 1995 when his supporters were caught installing phonelines for a leadership campaign HQ.

Mr Portillo was regarded by many in the Conservative Party as its natural leader, but partly through circumstance and partly through lack of judgement, he ultimately became its lost leader.

There are many still hoping that David Miliband, so long seen as the 'heir to Blair,' can avoid a similar fate.

One of them, possibly both, is going to end up a loser

Given that the British electorate as a whole only gets to vote once every 4-5 years, it is perhaps inevitable that by-elections tend to wield a somewhat disproportionate influence on our political process.

Usually they follow a fairly predictable pattern. The public – or the media – identifies which of the two main opposition parties is most likely to give the governing party a good kicking, and the 'protest vote' does the rest.

But we are in unchartered waters now. There are two governing parties, only one main opposition party, and the new-ish leader of that party is something of an unknown quantity to most voters.

All of which is what makes Thursday's Oldham and Saddleworth by-election possibly the most fascinating such encounter since the Darlington contest of 1983 which, to Labour's ultimate detriment, saved the leadership of Michael Foot.

On the face of it, it ought to be plan sailing for Labour. In a few short months, the Con-Lib coalition has slashed public spending, put up VAT, and scrapped much of the regional aid budget that was helping former industrial towns like Oldham to find a new role.

Not only that, but the seat was won by Labour in the general election last May, before MP Phil Woolas was disqualified from Parliament for having lied about his Lib Dem opponent on his election literature.

One of the many imponderables in this contest is whether the fate of Mr Woolas will help or hinder Labour's cause here.

The fact that he was actually quite a popular local MP might appear to favour the party, but some voters may feel he was too readily hung out to dry by the Labour establishment, and punish the party accordingly.

Inevitably given its status as a three-way marginal, 'Old and Sad' is being viewed as something of a mini-referendum – not just on the Coalition, but on Labour leader Ed Miliband.

If Labour cannot even win by-elections in seats it already holds, serious questions will start to be asked as to whether it can win anywhere else under Mr Miliband's leadership.

But for Lib Dem leader Nick Clegg, too, a defeat on Thursday would be seen as a significant blow.

His party's candidate, Elwyn Watkins, may well feel the seat is his by moral and indefeasible right having been on the wrong end of Mr Woolas's misdemeanours, but politics doesn't work like that.

Undoubtedly the leader with the least to lose and the most to gain here is Prime Minister David Cameron.

For one, the Conservative candidate Kashif Ali started the contest in third place. For another, the Tories have been accused of soft-pedalling their campaign in a bid to help their Lib Dem partners.

Perhaps realising he is in with an outside chance of a stunning victory Mr Cameron is now doing his best to dispel that impression, becoming the first premier to campaign in a by-election for 13 years.

Yet ironically a Tory win, in a seat where the Lib Dems began as the main challengers, might end up being more destabilising for the Coalition than a Labour triumph.

Mr Clegg would then face more tough questions from his own activists and MPs as to what exactly the Lib Dems are getting out of the Coalition.

A Tory victory would simply reinforce the idea that it is the Lib Dems who are taking all the political pain while Mr Cameron reaps the political dividends.

But whoever wins on Thursday, at least one and possibly both of Mr Cameron's fellow party leaders are going to be waking up to some difficult headlines on Friday morning.

And for either or both of them, that could set the tone for a tricky political year ahead.