Brendon McCullum was put in the firing line at No. 3, a waste of one of New Zealand's main assets © Getty Images
New Zealand's performance on the second day at Trent Bridge was when their resolve finally betrayed them, but also one that exposed a bold gamble as a failure. From the moment Brendon McCullum dropped Stuart Broad at second slip at the start of the day, England - not without the occasional slice of good fortune - dominated in the manner they have threatened but failed all year. New Zealand are renowned for their plucky resistance with the bat, but no longer can the cracks in their top-order be masked by lower-order doggedness.

That they slipped to 96 for 6 was due to James Anderson, who picked up all six wickets in a breathless 15-over spell of outswing bowling, but it hasn't always required brilliance for New Zealand's ambitions to be shattered. Their top six have simply not delivered. In England's tour during the winter, Jamie How averaged 33.5, Matthew Bell an unconvincing 19.5 and Mathew Sinclair 11.83. For New Zealand's return tour here, How has begun more promisingly, with scores of 68, 64, 29 and 40, but the others have continued to flounder. Aaron Redmond (52 runs at 10.40), Daniel Flynn (42 at 21.00) and James Marshall (52 at 13.00) have all been in the firing line, consistently picked off by England's four-man attack.

Though they are quick to dispel the notion of being scarred by the loss at Old Trafford, it was their reaction to being dismissed for 114 which provides the key to understanding today's batting failure. McCullum, shunted up the order to No.3, had his off stump pegged back for 9 by Anderson, and New Zealand's most dangerous and talented batsman had departed with the score on 14 for 2. In theory, McCullum's promotion was precisely what New Zealand needed - a touch of class to give succour to the raw recruits at the top of the order - but in practice, it was a disaster in the making.

Like a football team that is forever being pinned in its own half by superior opponents, New Zealand's cricketers are more than capable of springing regular surprises, but they invariably do so by taking their licks and hitting their opponents on the break. Using McCullum so far up front leaves him woefully out of position, because it is from No.6 backwards that New Zealand have been able to mask the frailties and failures of their top-order.

In Hamilton during the winter, McCullum (51) and Daniel Vettori (88) helped lift New Zealand from a tricky 191 for 5 to a match-winning 470. Likewise in Napier, though they lost the Test, McCullum and Vettori again spared their team's blushes with pairs of forties, helping New Zealand to recover from 172 for 5 to 431 all out. For a long time now, New Zealand's batting line-up has been the wrong way round - but the solution to rebalancing cannot lie in promoting their most prized asset, McCullum, into the disaster zone.

How provided a window into New Zealand's mindset when, after the second day's play, he spoke of his side's confidence in light of the precarious position they find themselves. "We take heart from Old Trafford," he said. "That game turned on its head pretty quickly, so hopefully that trend will continue. So hopefully we're only a couple of partnerships away from posting a good score, and anything can happen." Bold words indeed, but New Zealand are conditioned to believe that their tail will save them. More's the pity that, on this occasion, it has already been docked.

But then again, New Zealand's tried-and-tested formula - top-order debacle, tail-end revival - has been rudely challenged this summer by the emergence of Ross Taylor. Though he fell for 21 today, Taylor has displayed plenty of the star quality that New Zealand have lacked since the retirements of Stephen Fleming and Nathan Astle. His audacious 154 at Old Trafford was an innings of supreme quality, all the more so because it paid little heed to the familiar failings all around him - aside from How, no-one else in the top eight passed 40.

In truth, their hands were forced. In trailing the series 1-0, they need to win. And with McCullum's back injury forcing the call-up of their replacement keeper, Gareth Hopkins, New Zealand understandably chose a five-man attack, but in doing so have further weakened an already flimsy top-order.

Right now, New Zealand are caught between two mindsets. Taylor's successes - and, to a lesser extent, How's reliability - have persuaded them that there may yet be a future in following convention, and playing their best batsmen in their rightful position. But somehow they've lacked the courage of their convictions. Oram, for instance, appeared to be back to his best after his Lord's hundred. Since then, however, England have hounded him with bouncers, leaving him questioning his very worth. And in picking only five batsman, too great a responsibility rested on McCullum's shoulders.

Where is the logic in promoting McCullum but hiding Oram behind not only Gareth Hopkins, the debutant wicketkeeper, but also the grievously injured Daniel Flynn, who has far more of a right to be unsettled by the short ball after his experiences at Old Trafford? Vettori, who averages 40.83 in his last 10 Tests, might want to consider easing his way up from No. 8 as well if the McCullum experiment is to be continued, because right now it's not clear whether New Zealand are searching for leaders or followers.

Will Luke is a staff writer at Cricinfo