The Athletic has launched a Cricket WhatsApp Channel. Click here to join.It was meant to be a reset after the nadir of the Ashes, but England are in an even worse mess now than when they were embarrassed, on and off the field, in Australia.A famous triumph for New Zealand, sealed with a thumping 160-run win just after lunch on the last day of the deciding Test at Trent Bridge, was overshadowed by the soap opera surrounding England. That is grossly unfair on the victors, who have been superb since going one down at Lord’s and put in a display here full of proper Test cricket played by proper Test cricketers.This was a New Zealand team who lost their best batter, Kane Williamson, after the first Test and went into this decider without two key bowlers, Matt Henry and Kyle Jamieson, and their most consistent run scorer in the first two games, Glenn Phillips. One of those who came in, Blair Tickner, was lost to concussion on day two, while Will O’Rourke and Ben Sears suffered injuries during the match.And yet they still found a way.Contrast that with the self-defeating and, at times, self-indulgent approach by England, who now find themselves with seven defeats in their last nine Tests and with a first home defeat in a ‘major’ Test series since 2012.They now have a leadership vacuum they will struggle to fill, too.Joe Root trudges off at Trent Bridge after being run out early by Henry Nicholls (Gareth Copley/Getty Images)Where on earth England find a successor to Ben Stokes before their next Test assignment, against Pakistan in mid-August, is anyone’s guess and is the biggest problem facing managing director Rob Key and coach Brendon McCullum if — and it is a big if — they survive the fall-out.Surely they cannot give it to Harry Brook? Not after his irresponsible performance with the bat on Sunday that saw him slog 21 off nine balls before comically throwing it all away.The sight of New Zealand wicketkeeper Tom Blundell laughing at England’s vice-captain as he left the field and a voice in the New Zealand huddle shouting incredulously, “What are they doing?” said it all. Brook is no England Test captain. Not now. Possibly not ever. He is just too immature as a cricketer and as a person for the highest office.