James Cusick on Brown's D-Day

Crisis? What crisis? Very late on Thursday night or very early on Friday morning, once the votes have been counted in Glasgow East, Gordon Brown - whether he narrowly avoids defeat or whether Alex Salmond's forecast "earthquake" is already showing up on the Nationalists' self-righteous scale -will define his remaining time in office. He will have his "January 10", the day in 1979 when the prime minister Jim Callaghan flew back to London from Barbados and, faced with a country being torn to shreds by industrial relations chaos, food shortages, panic buying and a road haulage strike that was making everything scarce, held a press conference at Heathrow airport.

Callaghan was near exhaustion. He had been attending a summit on the Caribbean island of Guadeloupe, involving private talks with the US president Jimmy Carter which centred on the future of Britain's nuclear deterrent. Callaghan knew about the road haulage strike that had begun in Scotland just before he left. He'd been told about the escalation of the industrial action, but out of sight, out of mind, Callaghan was preoccupied with Pershing and Tomahawk missiles and hadn't switched back to British winter time and the discontent at home.

Asked at Heathrow about the effects of the industrial action, Callaghan looked like a man in denial. He said "I don't think other people in the world share the view that there is a mounting crisis." The Sun newspaper, already eager for the Thatcher years to begin, ran the headline "Crisis? What crisis?"

Self-denial, head in the sand, out of touch? It doesn't really matter what the analysis was. The headline and its wider message haunted Callaghan's reputation for decades and helped destroy what was already a decaying administration. For the remainder of January and February 1979 the chaos surrounding Number 10 got steadily worse.

If March 28 and the lost vote of confidence in the Commons was Callaghan's final failure, it was January 10 that started the process of downfall.

Denial is a poor defence at the best of times; denial in politics is a cardinal error. This Friday, if Brown and his senior ministers deny there is a real problem and say this after either crawling over the winning line having haemorrhaged votes, or portraying a slender SNP victory as no more than a routine mid-term grievance, then Brown will quickly go the same way as Sunny Jim.

Watching a 13,507 majority shrink or evaporate when a less than impressive SNP candidate is pitted against a seasoned and high-profile Labour opponent requires an explanation from Labour's senior ranks that so far has been absent in all the other crises Brown has endured over the past 12 months. The harsh reality is that Brown has won nothing since he entered Number 10, and if Glasgow East is the contest he just couldn't lose, where does that leave his electability, his credibility, and Labour's collective sanity if the Glasgow result is shrugged off as something that's to be survived as the party dives for cover into the summer recess?

Win by 500 votes, but lose 13,000, and there might be temptation for some to say that "a win's a win". Way too easy. It will also be too easy for Labour's by-election TV panellists on the night to begin by rolling out familiar excuses, such as "this is to be expected during a government's mid-term" or "of course we will react to the message we have been sent."

Denial permeated every explanation given after the result in Crewe and Nantwich, in which a safe northern England Labour seat, once off Tory radar, had just said no to Brown. The electorate of Crewe and Nantwich offered their verdict and no-one seemed to be listening. The local elections in England and Wales offered a similar verdict; the result in Henley, where the Labour candidate drifted in fifth behind the BNP, offered the uncomfortable conclusion that whatever Labour was now putting on sale, no-one was buying.

In the phantom election that never was, it wasn't that Brown showed weakness when confronted with a re-energised Tory party and their miracle cure of a promised cut in inheritance tax. His decision to call off a talked-up snap poll was a statistical one, a calculation that came down to "too much of a gamble". Had he confessed this, he would have been criticised, but the calculation would have been accepted as at least based in reality. But by denying his decision had anything to do with tightening polls, and repeating this again and again, Brown's credibility, and indeed his honesty, were diminished.

Other decisions should have made a greater impact on his premiership. Troop withdrawals from Iraq were promised but haven't materialised; the loosening of relations with George Bush's White House were initially choreographed, now the dance has been identified for what it was, fake; similarly, where is the constitutional reform and the reform that was supposed to bring in state funding for political parties?

Instead there has been the abolition of the 10p tax rate - an error in itself, but made worse by a denial, then a U-turn. And the successes? Ask, and you will be pointed to the introduction of 42 days detention for terrorist suspects and a quick-fire denial that this had anything to do with trying to out-manoeuvre the Conservatives on a security issue.

Brown's communications skills are poor to non-existent, his ability to look engaged and empathetic minimal. But denial and delusion have been his most damaging characteristics as, month on month, crisis on crisis, Labour's poll ratings have slumped to 20 points and more behind the Conservatives. And yet the constant message from Number 10 is that Brown remains the skilled and experienced politician who can take Britain out of what is being portrayed as just a little global difficulty in the economic cycle. Crisis? What crisis?

Lose Glasgow East, or sneak a victory, and either way a sane explanation has to be offered up by those around Brown. The delusional should be shunted into their own freak show. For others, a competent explanation will have to be offered as to why former Labour supporters deserted in droves and why voters who say they don't want independence for Scotland, and are at the bottom of the wealth scale, are being persuaded that the SNP offers them a greater chance of economic salvation.

Of course, if there is no credible explanation, there is only one credible outcome.

Just as Callaghan was gone in a matter of months after January 10, Brown may have his date marked - it may well be July 24, 2008.