England closing in on series victory
The late incisions made by Anderson and Ryan Sidebottom mean the task facing England to wrap up the series isn't too daunting. But McCullum and Flynn at least made them expend more energy than the first innings with their fourth-wicket stand of 94. McCullum reined in his aggressive instincts with a 103-ball half-century, countering the swing by standing well out of his crease, which helped him survive a couple of lbw shouts.
England were just beginning to wonder where the breakthrough would come from when Anderson, returning for a late spell, produced one to nip back through McCullum's defences. Then Flynn, whose innings had been characterised by his unwillingness to chase anything wide, momentarily lost his composure and flashed at Sidebottom, one short of his maiden fifty. However, his 105-ball stay at least showed he'd overcome any lingering doubts following his nasty injury at Old Trafford.
The follow-on has gone out of fashion in Test cricket, partly because the rate of scoring means there is often time for a team to bat themselves back into the match. Michael Vaughan may have been in two minds about sticking New Zealand back in, but their first innings ended so swiftly - the final three wickets falling for no runs in six balls - that it become a more comfortable decision. Everything pointed Vaughan in that direction, from the dank, overcast weather, to the demoralised New Zealand top order which had to face the music again, 241 runs behind.
For a period, a three-day finish was looking a distinct possibility as the fragility of the visitors was exploited for the second day running. Aaron Redmond's miserable series continued and, if he couldn't do much about his first-innings dismissal, this time he played a shot that doesn't belong to a Test opener, chasing a full ball from Broad and edging through to Tim Ambrose. Broad was the pick of England's attack, outshining Anderson and Sidebottom, who both struggled with their lines. Following his maiden half-century on Friday, it was timely reward for Broad with the ball after a barren Test at Old Trafford.
McCullum, remaining at No. 3, responded as he did in the first innings with some powerful cover drives, but England - and especially Broad - thought they had him on 12 when one appeared to graze the outside edge, only for Darrell Hair to stay unmoved.
Next over, however, a fired-up Sidebottom won a brief duel with Jamie How with a clever piece of bowling by holding the ball cross-seam to prevent it swinging too much. It drew How into pushing at one he could have left, and Alastair Cook held a neat catch at third slip. Ross Taylor briefly counter-attacked, but his flamboyant game is not made for grafting in swinging conditions. His wild mow across the line against Broad belied his quality and was another ugly dismissal.
Record books were poised, if not quite open, when Anderson began the day with a chance of becoming just the third man to take all ten wickets in a Test innings. It is one of the curiosities of sport that someone who is so dominant one day can lose the Midas touch overnight, and in the end he had settle for a career-best 7 for 43.
The ball swung far more than yesterday, which actually proved a disadvantage to the England attack, as they resumed the search for New Zealand's last four wickets after drizzle prevented any play before lunch. Anderson twice sprayed four byes down the leg side, while Sidebottom fired one delivery between first and second slip for five wides.
But it was only a question of when they would find their lines, and the breakthrough came as Daniel Vettori got a thick edge, forcing off the back foot, to Andrew Strauss at first slip. Broad struck twice in his first - and only over - when Kyle Mills chased a full, wide delivery and sent a high catch to Kevin Pietersen at point. Two balls later, Broad produced a beauty to match Anderson's corkers which sent Iain O'Brien's off stump backwards.
Hopkins was the last man out, giving Anderson his first-class best, and New Zealand's plight was summed up when he was back at the crease before the day was out. After having moments of superiority during the first two Tests, New Zealand are finishing the series a distant second best.
Andrew McGlashan is a staff writer at Cricinfo