Just before it is expunged from history, let's pause for a moment to remember Ed Miliband's address to Scottish Labour's spring conference.

It wasn't very good, was it?

In fact, it was one of those speeches that would struggle to be dismissed as desultory. If Mr Miliband was sincere in every cliched word, his party doesn't have its problems to seek, north or south of the Border.

The overarching issue before the Labour leader was one of identity. How could he describe his party and what it these days represents? How could he distinguish it from its rivals and their competing claims? In particular, what was the Labour alternative in the argument over independence?

The venerable tactic of painting the SNP as Tartan Tories was one place to start. Nationalist sincerity in the pursuit of social justice would be disputed in an effort to clear ground for Labour's devolution commission. Alex Salmond's promise to keep corporation tax below any level adopted by a remnant UK could thus be assailed as "a race to the bottom".

But how does that stack up? Mr Miliband's party is in alliance with those self-same Tories in the Better Together campaign. He and Ed Balls have embraced both George Osborne's spending limits and his welfare cap. The commission's contention that income tax can be increased but never cut by a devolved parliament is, to be polite, incoherent. And didn't Gordon Brown cut corporation tax more than once?

Mr Miliband was promoting an odd prospectus, then, but his delivery was at least as problematic as the content of his speech. He sounded very like a man going through the motions. Worse (for Labour) he sounded about as comfortable before a Scottish audience as Tony Blair. Not for the first time, the present leader struggled to sound credible.

So Mr Miliband spoke badly: these things happen. But the Labour leader also spoke, as no doubt he must, as though he would be forming a government in just over a year. His claim to lead the only party ready to deliver social justice (welfare cap permitting) depended on that belief. So too did a parallel argument: Scotland need not succumb to the allure of independence when Labour stands ready to build a better Britain.

In one section of his speech, Mr Miliband made a claim that has become a commonplace of leftish Unionism. He said: "People should not believe the SNP argument that there is a Tory England and a progressive Scotland."

This is an old but important claim for those who want to preserve the UK. Some of them invoke all sorts of attitudes surveys to show Scots are just as right-wing as folk below the Border on issues such as immigration or social security spending. Confusingly, some of the same polemicists argue "progressive" belief is alive and well in the south.

A pity about the polls and the election results, then. Fair's fair: we can leave the latter aside, given Mr Miliband has more than a year in which to make his own case to voters, if he can. The former meanwhile contain two messages.

One is that Scotland and England continue to diverge in their political tastes. Neither polls not election results are ambiguous. The Ukip phenomenon has no echo here. The appeal of Conservatism is also limited, let's say, despite special pleading from Scottish Tories who can sound like secret enthusiasts for PR when they talk about their "real" support. The other message is a personal one for Mr Miliband.

It's not going so well. In fact, given what the people of these islands have gone through since the financial crash, given the actions of the coalition, given widespread insecurity and austerity without end, it is going very badly indeed. Mr Miliband is deep in something. And it is not redolent of the sweet smell of success.

Two polls at the weekend showed Labour with just a single point advantage over the Conservatives. On Monday, a third poll told the same story. Two further surveys showed Mr Miliband's party with a two point lead and a five point advantage. The second result was two percentage points down, however, on previous polling. No opposition party in the world would be happy with that bunch of statistics.

They can be rationalised, of course, as all bad news can be rationalised. Labour people can say, for example, that Mr Osborne has earned the Tories nothing more than a temporary "Budget bounce". But that only works if you overlook Mr Miliband's feeble response to the Budget and Labour's failure to promote alternatives.

Party loyalists can also point that even these grim tidings do not tell the whole story. Thanks to remarkable quirks in the electoral system, Labour could still wind up with a majority of 30-odd seats if an election was held tomorrow and the polls proved accurate. Mr Miliband doesn't truly have to win, it's said. He just has to avoid losing.

That's not exactly inspirational, you might have thought, but never mind. Anyone inclined to worry over Labour's prospects needs to consider a few other pieces of polling evidence. They involve issues which are, says the usual wisdom, crucial to a party's chances. One has to do with economic competence, the other with a leader's "personal rating".

On the first of these, a weekend Survation poll said that while 39% trust Mr Osborne with the economy - austerity, pasty taxes and all - only 29% put the same faith in Ed Balls, the shadow Chancellor. Meanwhile, YouGov found on March 20 to March 21 that while David Cameron has a "doing well/doing badly" rating of minus 9%, the figure for Mr Miliband emerges as minus 31%. In other words, 60% of those asked just don't rate the Labour leader.

Some of his MPs are voicing their unease. Think tanks on the left, those factional front organisations, have been chipping in with advice on the devolution of power, the revival of local government and the need for boldness. No one will yet say the game is up. The bookies still have Labour at 8/11 for an outright Westminster majority. The Tories, though, stand at a very decent 6/4. Mr Cameron would take those odds.

What Mr Miliband means by social justice when he and Mr Balls, armed with a "zero-based" spending review, are promising still more cuts is anyone's guess. Labour's short-term offer amounts to little more than a redistribution of the social and economic pain. The Tories are still a long way short of a lead in those polls, but a resumption of coalition government after May 2015 is another matter.

Some will tell you it was always an enormous challenge for Labour to return to government in a single bound. One school of thought (this one) says instead that if Mr Miliband can't beat the Tories hands down now his chances in the future can only recede.

Voters neither believe in him nor trust him. It is the central fact of British politics. It is also a large, inescapable fact in Scotland's long argument over independence. There is no Labour escape route. All the talk of social justice one day is just talk.